CN109194097B - Switching power supply control circuit and method and switching power supply - Google Patents
Switching power supply control circuit and method and switching power supply Download PDFInfo
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- CN109194097B CN109194097B CN201811146178.1A CN201811146178A CN109194097B CN 109194097 B CN109194097 B CN 109194097B CN 201811146178 A CN201811146178 A CN 201811146178A CN 109194097 B CN109194097 B CN 109194097B
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- 238000000034 method Methods 0.000 title claims abstract description 14
- 230000001105 regulatory effect Effects 0.000 claims description 25
- 230000001939 inductive effect Effects 0.000 claims description 24
- 230000003111 delayed effect Effects 0.000 claims description 7
- 230000002093 peripheral effect Effects 0.000 abstract description 8
- 230000008901 benefit Effects 0.000 abstract description 5
- 230000005540 biological transmission Effects 0.000 abstract description 3
- 238000005070 sampling Methods 0.000 abstract description 3
- 230000001934 delay Effects 0.000 abstract 1
- 239000003990 capacitor Substances 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 238000004891 communication Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 238000002955 isolation Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000002035 prolonged effect Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 230000003750 conditioning effect Effects 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
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- Dc-Dc Converters (AREA)
Abstract
The invention discloses a switching power supply control circuit and method and a switching power supply, wherein the switching power supply control circuit delays the switching on of a main switching tube of the switching power supply at a first time after the follow current of an auxiliary switching tube is completed, and adjusts an inductance current peak value or/and the first time according to the follow current time and a reference time of the auxiliary switching tube so as to control the output voltage of the switching power supply to be a preset voltage. The invention has the advantages of simple circuit, fewer peripheral devices, no need of sampling the output voltage and flexible output voltage setting while controlling the constant output voltage of the switch power supply, and can realize the information transmission of the primary side and the secondary side of the switch power supply without peripheral circuits such as optocouplers in the switch power supply.
Description
Technical Field
The present invention relates to the field of power electronics, and in particular, to a switching power supply control circuit and method, and a switching power supply.
Background
The application of the output constant voltage control of the switching power supply is particularly wide. For example, in the field of intelligent dimming, the output load of a switching power supply often includes other communication modules, such as a wireless module/bluetooth module, in addition to LEDs. As shown in fig. 1, the output terminal Vout of the switching power supply is connected to an LED, and is connected to a post-stage communication module (denoted by R1 in fig. 1) through a linear regulator. When the LED works, the power supply of the rear-stage communication module is easy to realize; when the LED is in standby, the power consumption problem is considered, and the switching power supply is required to output a constant voltage which is far smaller than the voltage drop of the lamp so as to realize normal power supply of the communication module.
In the prior art, the output voltage of the switching power supply is collected, and the collected difference value between the output voltage and the reference voltage is utilized to adjust the output voltage in a closed loop mode, so that the output voltage is maintained at the reference voltage, the voltage closed loop control is realized, and the output voltage of the switching power supply is constant.
However, for an isolated switching power supply, primary and secondary side voltages are isolated, an auxiliary winding or an optocoupler is required for collecting output voltage, the output voltage is not flexibly set, more peripheral devices are required, and a circuit is complex; for non-isolated switching power supply, can be provided with a FB pin in integrated circuit, sample switching power supply's output voltage through the FB pin, the FB pin can take place short circuit, contact failure scheduling problem for constant voltage control can not reach the effect, and if need not gather output voltage, can save the FB pin, thereby reduce the cost.
Disclosure of Invention
The invention aims to provide a switching power supply control circuit and method with fewer peripheral devices and flexible output voltage setting, and a switching power supply, and solves the technical problems that the setting of the output voltage is inflexible, more peripheral devices are needed, the circuit is complex and the output voltage needs to be sampled in the prior art.
In order to achieve the above purpose, the present invention provides a control circuit for a switching power supply, wherein after the follow current of an auxiliary switching tube is completed, the main switching tube of the switching power supply is turned on at a first time in a delayed manner, and the peak value of the inductor current is adjusted or/and the first time is adjusted according to the follow current time and the reference time of the auxiliary switching tube, so that the output voltage of the switching power supply is controlled to be a preset voltage.
Optionally, after the inductor current in the switching power supply reaches a preset peak value, the main switching tube is turned off, and the auxiliary switching tube starts to freewheel; and starting when the inductance current is lower than a first threshold value, and after the first time is delayed, switching on a main switching tube of the switching power supply.
Optionally, the reference time is proportional to a difference between the inductor current preset peak value and the first threshold value.
Optionally, when the freewheel time of the auxiliary switching tube is smaller than the reference time, reducing the peak value of the inductive current or/and prolonging the first time, so that the output voltage is reduced;
when the follow current time of the auxiliary switching tube is larger than the reference time, the peak value of the inductive current is increased or/and the first time is shortened, so that the output voltage rises.
Optionally, when the first time is lower than the second threshold, the output voltage is maintained at the preset voltage by adjusting the peak value of the inductor current;
When the peak value of the inductor current is lower than a third threshold value, the output voltage is maintained at a preset voltage by adjusting the first time.
Optionally, the switching power supply control circuit includes error amplifier and delay circuit, error amplifier's first input terminal receives the voltage signal that represents auxiliary switch tube freewheel time, error amplifier's second input terminal receives the voltage signal that represents reference time, error amplifier output connects delay circuit's input, delay circuit's output passes through the control end of logic circuit connection switching power supply main switch tube, delay circuit adjusts first time.
Optionally, the switching power supply control circuit further includes a peak value adjusting circuit, an input end of the peak value adjusting circuit is connected with an output end of the error amplifier, an output end of the peak value adjusting circuit is connected with a control end of a main switching tube of the switching power supply through a logic circuit, and the peak value adjusting circuit adjusts an inductance current peak value.
Optionally, the switching power supply control circuit includes error amplifier and peak value regulating circuit, error amplifier's first input terminal receives the voltage signal that represents auxiliary switch tube freewheel time, error amplifier's second input terminal represents the voltage signal of reference time, error amplifier output terminal is connected peak value regulating circuit's input, peak value regulating circuit's output passes through the control end of logic circuit connection switching power supply main switch tube, peak value regulating circuit adjusts the inductance current peak value.
The invention also provides a control method of the switching power supply, which comprises the following steps:
After the follow current of the auxiliary switching tube is completed, delaying the switching of the main switching tube of the switching power supply at the first time;
and adjusting the peak value of the inductive current or/and the first time according to the follow current time and the reference time of the auxiliary switching tube, thereby controlling the output voltage of the switching power supply to be a preset voltage.
Optionally, after the inductor current in the switching power supply reaches a preset peak value, the main switching tube is turned off, and the auxiliary switching tube starts to freewheel; and starting when the inductance current is lower than a first threshold value, and after the first time is delayed, switching on a main switching tube of the switching power supply.
Optionally, the reference time is proportional to a difference between the inductor current peak value and the first threshold value.
Optionally, when the freewheel time of the auxiliary switching tube is smaller than the reference time, reducing the peak value of the inductive current or/and prolonging the first time, so that the output voltage is reduced;
when the follow current time of the auxiliary switching tube is larger than the reference time, the peak value of the inductive current is increased or/and the first time is shortened, so that the output voltage rises.
Optionally, when the first time is lower than the second threshold, the output voltage is maintained at the preset voltage by adjusting the peak value of the inductor current;
When the peak value of the inductor current is lower than a third threshold value, the output voltage is maintained at a preset voltage by adjusting the first time.
The invention also provides a switching power supply, which comprises any one of the switching power supply control circuit and the power circuit.
Compared with the prior art, the technical scheme of the invention has the following advantages: according to the invention, after the follow current of the auxiliary switching tube of the switching power supply is completed, the main switching tube of the switching power supply is started at a first time in a delayed manner, and the first time or/and the inductive current peak value is regulated through the follow current time and the reference time of the auxiliary switching tube, so that the output voltage of the switching power supply is regulated, and the output voltage of the switching power supply is controlled to be a preset voltage. The control method of the switching power supply controls the constant output voltage of the switching power supply, and has the advantages of simple circuit, fewer peripheral devices, no need of sampling the output voltage and flexible output voltage setting. The invention is suitable for the isolated and non-isolated switching power supplies, has great advantages in the isolated switching power supplies, and can realize the information transmission of the primary side and the secondary side of the isolated switching power supplies without peripheral circuits such as optocouplers and the like.
Drawings
FIG. 1 is a circuit schematic diagram of a prior art switching power supply control circuit;
FIG. 2 is a schematic diagram of a switching power supply control circuit according to an embodiment of the present invention;
FIG. 3 is a waveform diagram illustrating the operation of the switching power supply control circuit of the present invention;
Fig. 4 is a circuit diagram of the generation of a voltage signal characterizing the freewheel time of an auxiliary switching tube according to the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to these embodiments only. The invention is intended to cover any alternatives, modifications, equivalents, and variations that fall within the spirit and scope of the invention.
In the following description of preferred embodiments of the invention, specific details are set forth in order to provide a thorough understanding of the invention, and the invention will be fully understood to those skilled in the art without such details.
The invention is more particularly described by way of example in the following paragraphs with reference to the drawings. It should be noted that the drawings are in a simplified form and are not to scale precisely, but rather are merely intended to facilitate and clearly illustrate the embodiments of the present invention.
The invention provides a switching power supply control circuit, which is used for delaying the switching on of a main switching tube of a switching power supply at a first time after the follow current of an auxiliary switching tube is finished, and adjusting an inductance current peak value or/and the first time according to the follow current time and a reference time of the auxiliary switching tube so as to control the output voltage of the switching power supply to be a preset voltage. Specifically, according to the follow current time and the reference time of the auxiliary switching tube in the current period, the peak value of the first period or the next period of the current period is adjusted.
The reference time is proportional to the difference between the inductor current peak and the first threshold. When the reference time Tref represents that the output voltage of the switching power supply is a preset voltage V1 and the difference value between the inductive current peak value and the first threshold value is Ipeak-I0, the corresponding auxiliary switching tube freewheel time, namely tref= (Ipeak-I0) ×l/V1, so that tref=k× (Ipeak-I0) and k=l/V1 are proportional to the same circuit, namely the reference time Tref is proportional to the difference value between the inductive current peak value and the first threshold value.
The switching power supply is controlled by a peak value, namely after the inductance current in the switching power supply reaches a preset peak value, the main switching tube is turned off, and the auxiliary switching tube starts to freewheel; and starting when the inductance current is lower than a first threshold value, and after the first time is delayed, switching on a main switching tube of the switching power supply.
When the output voltage is higher than the preset voltage, the follow current time of the auxiliary switching tube is smaller than the reference time, and the peak value of the inductive current is reduced or/and the first time is prolonged, so that the output voltage is reduced; when the output voltage is lower than the preset voltage, the follow current time of the auxiliary switching tube is longer than the reference time, and the peak value of the inductive current is increased or/and the first time is shortened, so that the output voltage is increased.
The switching power supply control circuit can stabilize the output voltage only by adjusting the first time or only adjusting the peak value of the inductive current, can stabilize the output voltage by adjusting the first time and the peak value of the inductive current at the same time, and can achieve the purpose by respectively selecting and adjusting the first time, the peak value of the inductive current or the first time and the peak value of the inductive current in different time periods or different states. If the output power is too high, the first time is lower than the second threshold, and the peak value of the inductor current is adjusted to maintain the output voltage at the preset voltage; when the output power is too small, the peak value of the inductance current is lower than a third threshold value, and the output voltage is maintained at a preset voltage by adjusting the first time.
The second threshold and the third threshold described above may be set according to actual practice, and the present invention is not limited to specific values thereof.
As shown in fig. 2, a specific structure of one embodiment of the switching power supply control circuit is illustrated. The voltage signal V T2 representing the follow current time T2 of the auxiliary switching tube is received by a first input end of the error amplifier U1, a voltage signal Vref representing the reference time Tref is received by a second input end of the error amplifier U1, a compensation signal is output to the delay circuit and the peak regulating circuit by the error amplifier U1, the output ends of the delay circuit and the peak regulating circuit are connected with the control end of the main switching tube of the switching power supply through the logic circuit, the output end of the error amplifier is connected with one end of the capacitor C1, the other end of the capacitor C1 is grounded, and the voltage on the capacitor C1 is Vcom.
The working waveform diagram of the switching power supply control circuit is shown in fig. 3, wherein iL is the inductance current of the switching power supply, T1 is the first time, and T2 is the auxiliary switching tube freewheel time. It can be seen that the switching power supply is controlled to be in peak value control, and after the inductance current reaches a preset peak value, the main switching tube is turned off, and the auxiliary switching tube starts to follow current; and starting when the inductance current is lower than a first threshold value, and after a first time T1, switching on a main switching tube of the switching power supply. The first threshold value may theoretically be any value, and in an embodiment of the present invention, the first threshold value is zero. The off-time Toff of the main switching tube is equal to the sum of the freewheel time T2 and the delay time T1 of the auxiliary switching tube, i.e. toff=t1+t2.
In this embodiment, when the output voltage changes, according to the voltage signal V T2 representing the freewheel time T2 of the auxiliary switching tube and the voltage signal Vref representing the reference time Tref, the peak value Vpeak of the inductor current is adjusted or/and the first time T1 is adjusted, so as to control the output voltage of the switching power supply to be the preset voltage V1.
The change trend of the output voltage Vout of the switching power supply and the change trend of the follow current time T2 of the auxiliary switching tube are opposite.
The specific adjusting process is as follows:
1) When the output voltage Vout of the switching power supply is larger than a set value V1, the follow current time T2 of the auxiliary switching tube is shortened, the follow current time T2 of the auxiliary switching tube is smaller than the reference time Tref, a voltage signal V T2 representing the follow current time T2 of the auxiliary switching tube in the current period is smaller than a voltage signal Vref representing the reference time Tref, namely V T2 is smaller than Vref, the output voltage of the error amplifier U1 is increased, namely Vcom is increased, the peak value of the inductance current is reduced or/and the first time is prolonged, and therefore the output voltage Vout is reduced;
2) When the output voltage Vout of the switching power supply is smaller than a set value V1, the follow current time T2 of the auxiliary switching tube is prolonged, the follow current time T2 of the auxiliary switching tube is larger than the reference time Tref, a voltage signal V T2 representing the follow current time T2 of the auxiliary switching tube in the current period is larger than a voltage signal Vref representing the reference follow current time Tref of the auxiliary switching tube, namely V T2 is smaller than Vref, the output voltage of the error amplifier U1 is reduced, namely Vcom is reduced, an inductance current peak value is increased or/and the first time is shortened, and therefore the output voltage Vout is increased;
3) Repeating the processes 1) and/or 2) until the output voltage of the switching power supply is the preset voltage V1.
In the adjusting processes 1) and 2), the first time stable output voltage can be adjusted only by the delay circuit, the peak value stable output voltage of the inductor current can be adjusted only by the peak value adjusting circuit, the first time and the peak value stable output voltage of the inductor current can be simultaneously adjusted by the delay circuit and the peak value adjusting circuit, and the three adjusting modes can be respectively selected in different time periods or different output states. In a preferred embodiment, when the output power is too high, the first time is lower than the second threshold value, and the reference time is adjusted by adjusting the peak value of the inductor current, so that the output voltage is maintained at the preset voltage; when the output power is too small, the peak value of the inductive current is lower than a third threshold value, and the output voltage is maintained at a preset voltage by adjusting the first time.
The invention has been given only in one embodiment, and in other embodiments there may be only a delay circuit or only a peak conditioning circuit.
As shown in fig. 4, a circuit for generating a voltage signal for representing the freewheel time of an auxiliary switching tube is provided, which comprises a current detection circuit, a current source I1, a switch S1 and a capacitor C2, wherein the current source I1, the switch S1 and the capacitor C2 are sequentially connected in series at two ends of a power supply, and the current detection circuit is connected with a control end of the switch S1. When the current detection circuit detects that the inductance current reaches the peak current, the switch S1 is closed, the current source I1 starts to charge the capacitor C2, when the current detection circuit detects that the inductance current value is zero, the switch S1 is disconnected, the current source I1 stops supplying power to the capacitor C2, and at the moment, the voltage on the capacitor C2 is the voltage signal V T1 representing the follow current time of the auxiliary switching tube.
The peak value regulating circuit comprises a comparator, one end of the comparator receives a first reference voltage Vref1, the other end of the comparator collects the inductance current of the switching power supply through a sampling resistor, and the output end of the comparator is connected with the logic circuit. When the peak value of the inductor current needs to be regulated up, the first reference voltage Vrefl is regulated up, and when the peak value of the inductor current needs to be regulated down, the first reference voltage Vref1 is regulated down.
In addition, in the embodiment shown in fig. 2, the auxiliary switching tube freewheel time T2 and the reference time Tref are converted into the voltage signal for comparison, and in other embodiments, other manners of comparison such as directly performing time comparison may be also used, which are all within the scope of the present invention.
The invention is suitable for the output constant voltage control of the isolation type switch and the non-isolation type switch, and in the isolation type switch power supply, an auxiliary winding or an optocoupler is not needed to carry out the complex peripheral circuit, and the information transmission of the primary side and the secondary side can be directly carried out, so that the advantage is more obvious.
Although the embodiments have been described and illustrated separately above, and with respect to a partially common technique, it will be apparent to those skilled in the art that alternate and integration may be made between embodiments, with reference to one embodiment not explicitly described, and reference may be made to another embodiment described.
The above-described embodiments do not limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the above embodiments should be included in the scope of the present invention.
Claims (10)
1. A switching power supply control circuit, characterized in that: after the follow current of the auxiliary switching tube is finished, delaying to turn on the main switching tube of the switching power supply at the first time, and adjusting the peak value of the inductive current or/and the first time according to the follow current time and the reference time of the auxiliary switching tube so as to control the output voltage of the switching power supply to be a preset voltage;
the reference time characterizes the output voltage of the switching power supply as preset voltage and the follow current time of the auxiliary switching tube, and is proportional to the difference value between the inductance current peak value and the first threshold value;
when the follow current time of the auxiliary switching tube is smaller than the reference time, reducing an inductive current peak value or/and prolonging first time, so that the output voltage is reduced;
when the follow current time of the auxiliary switching tube is larger than the reference time, the peak value of the inductive current is increased or/and the first time is shortened, so that the output voltage rises.
2. The switching power supply control circuit according to claim 1, wherein: after the inductance current in the switching power supply reaches a preset peak value, the main switching tube is turned off, and the auxiliary switching tube starts to follow current; and starting when the inductance current is lower than a first threshold value, and after the first time is delayed, switching on a main switching tube of the switching power supply.
3. The switching power supply control circuit according to claim 1, wherein: when the first time is lower than the second threshold value, the peak value of the inductive current is regulated, so that the output voltage is maintained at the preset voltage;
When the peak value of the inductor current is lower than a third threshold value, the output voltage is maintained at a preset voltage by adjusting the first time.
4. The switching power supply control circuit according to claim 1, wherein: the switching power supply control circuit comprises an error amplifier and a delay circuit, wherein a first input end of the error amplifier receives a voltage signal representing the follow current time of the auxiliary switching tube, a second input end of the error amplifier receives a voltage signal representing the reference time, an output end of the error amplifier is connected with an input end of the delay circuit, an output end of the delay circuit is connected with a control end of the switching power supply main switching tube through a logic circuit, and the delay circuit adjusts the first time.
5. The switching power supply control circuit according to claim 4, wherein: the switching power supply control circuit further comprises a peak value regulating circuit, wherein the input end of the peak value regulating circuit is connected with the output end of the error amplifier, the output end of the peak value regulating circuit is connected with the control end of the switching power supply main switching tube through a logic circuit, and the peak value regulating circuit regulates the peak value of the inductive current.
6. The switching power supply control circuit according to claim 1, wherein: the switching power supply control circuit comprises an error amplifier and a peak value regulating circuit, wherein a first input end of the error amplifier receives a voltage signal representing the follow current time of the auxiliary switching tube, a second input end of the error amplifier receives a voltage signal representing the reference time, an output end of the error amplifier is connected with an input end of the peak value regulating circuit, an output end of the peak value regulating circuit is connected with a control end of a main switching tube of the switching power supply through a logic circuit, and the peak value regulating circuit regulates an inductance current peak value.
7. A switching power supply control method comprising the steps of:
After the follow current of the auxiliary switching tube is completed, delaying the switching of the main switching tube of the switching power supply at the first time;
According to the follow current time and the reference time of the auxiliary switching tube, the peak value of the inductive current is regulated or/and the first time is regulated, so that the output voltage of the switching power supply is controlled to be a preset voltage;
the reference time characterizes the output voltage of the switching power supply as preset voltage and the follow current time of the auxiliary switching tube, and is proportional to the difference value between the inductance current peak value and the first threshold value;
when the follow current time of the auxiliary switching tube is smaller than the reference time, reducing an inductive current peak value or/and prolonging first time, so that the output voltage is reduced;
when the follow current time of the auxiliary switching tube is larger than the reference time, the peak value of the inductive current is increased or/and the first time is shortened, so that the output voltage rises.
8. The switching power supply control method according to claim 7, wherein: after the inductance current in the switching power supply reaches a preset peak value, the main switching tube is turned off, the auxiliary switching tube starts to freewheel, the inductance current is lower than a first threshold value, and after the first time is delayed, the main switching tube of the switching power supply is turned on.
9. The switching power supply control method according to claim 7, wherein: when the first time is lower than the second threshold value, the peak value of the inductive current is regulated, so that the output voltage is maintained at the preset voltage;
When the peak value of the inductor current is lower than a third threshold value, the output voltage is maintained at a preset voltage by adjusting the first time.
10. A switching power supply comprising a switching power supply control circuit as claimed in any one of claims 1 to 6.
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| CN201811146178.1A CN109194097B (en) | 2018-09-28 | 2018-09-28 | Switching power supply control circuit and method and switching power supply |
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| CN201811146178.1A CN109194097B (en) | 2018-09-28 | 2018-09-28 | Switching power supply control circuit and method and switching power supply |
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| CN104578790A (en) * | 2014-12-29 | 2015-04-29 | 东南大学 | Digital signal sampling circuit applied to primary-side feedback flyback converter and control method of digital signal sampling circuit |
| CN107769566B (en) * | 2017-03-28 | 2023-07-18 | 杰华特微电子股份有限公司 | Isolation type switch circuit and control method thereof |
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