CN105897015A - PSR constant-current constant-voltage AC/DC chip - Google Patents

Abstract

The invention relates to a PSR constant current and constant voltage AC/DC chip, which includes a control chip and a PSR flyback transformer. The control chip includes a software drive module, a constant current loop module, a constant voltage loop module, a soft drive module, and a PSR flyback The exciting transformer is connected to the constant current loop module through the feedback circuit module, and the SR flyback transformer is connected to the constant voltage loop module through the sampling circuit module. The output terminals of the constant current loop module and the constant voltage loop module are respectively connected to The soft drive module is connected. Compared with the prior art, the present invention proposes a high-precision constant-current constant-voltage chip design, which greatly improves the precision of output voltage and output current. At the same time, the system has high overall efficiency and stability, and the coordination and cooperation of the modules in the chip make the chip have high working performance.

Description

A PSR constant current constant voltage AC/DC chip

technical field

The invention relates to the field of constant current and constant voltage control chips, in particular to a PSR constant current and constant voltage AC/DC chip.

Background technique

In today's society, more and more electronic devices are used in people's daily life and work. The function of the power management chip is equivalent to the "heart" of electronic equipment, which plays a role in the management of electric energy conversion, distribution, safety detection and efficient work for electronic equipment. Up to now, switching power supply has been widely used in various electronic communication equipment, and has gradually become an indispensable key core technology in the rapid development of modern electronic information industry. With the development of semiconductor manufacturing technology and the continuous improvement of integrated circuit technology, switching power supply technology continues to develop in the traditional direction of high integration, high efficiency, high reliability, low noise and anti-electromagnetic interference. The current high-speed charging solution has inevitable disadvantages: poor compatibility, high charger cost, and large volume. The proposal of the fast charging scheme poses new challenges to the design of power management chips, and at the same time, it is of great significance to the development of switching power supplies.

Contents of the invention

The purpose of the present invention is to provide a PSR constant current and constant voltage AC/DC chip, which can effectively solve the above problems, precisely control the output constant current and constant voltage accuracy, and at the same time ensure the simplification and high efficiency of the system.

To achieve the above object, the present invention adopts the following technical solutions:

A PSR constant-current constant-voltage AC/DC chip is characterized in that: it includes a control chip and a PSR flyback transformer, and the control chip includes a software drive module, a constant-current loop module, a constant-voltage loop module, a soft drive module, and a PSR The flyback transformer is connected to the constant current loop module through the feedback circuit module, and the SR flyback transformer is connected to the constant voltage loop module through the sampling circuit module. The output terminals of the constant current loop module and the constant voltage loop module are respectively Connect with soft drive module. The chip also includes a new sampling control module and soft drive module, as well as overvoltage and undervoltage, overtemperature protection and oscillator modules.

The specific scheme is: PSR flyback transformer includes auxiliary coil winding composed of winding NAUX, primary winding NP and secondary winding NS, and diodes D0 and D1; the negative pole of diode D1 is divided into two ways to connect one end of capacitor C0 and resistor One end of R3, the anode of the diode D1 and one end of the primary winding NP are all connected to the drain of the power transistor M0, the capacitor C0, the resistor R3 and the other end of the primary winding NP are connected to the absorption circuit, and the gate of the power transistor M0 is connected to The G pin of the control chip and the source of the power transistor M0 are connected in two ways to the CS pin of the control chip and one end of the resistor RS, one end of the winding NAUX is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to one end of the resistor R2. Connection, the contact between the resistors R1 and R2 is connected to the FB pin of the control chip, the other end of the resistor RS, the resistor R2, and the winding NAUX are connected to the external signal; one end of the secondary winding NS is connected to the anode of the diode D0, and the diode D0 The negative electrode is divided into two circuits and connected to one end of the capacitor C1 and one end of the resistor R0 respectively, and the other ends of the capacitor C1 and the resistor R0 are both connected to the other end of the secondary winding NS. Among them: the CS pin is used to collect external circuit information and feed it back to the current-limiting comparator to determine the shutdown of the power tube; the FB pin is used to feed back the information indicating the output voltage change after the resistor divider to the control chip; It is used to control the external power tube M0.

The sampling circuit module includes a transistor Vbias and an operational amplifier CA. VDD is connected to the source of the transistor Vbias, the drain of the transistor Vbias is connected to the source of the transistor M9, and the non-inverting terminal of the operational amplifier CA is respectively connected to the drains of the transistors M9, M1, and M2. The inverting terminal of the amplifier CA is respectively connected to the drains of the transistors M5, M6, M7, M8 and one terminal of the capacitor C2, the output terminal of the operational amplifier CA is connected to the sampling information output terminal SH, and the source of the transistor M1 is divided into three ways and respectively connected to the transistor M3 The drain of the transistor, one end of the capacitor C0, the source of the transistor M8, and the source of the transistor M2 are connected in three ways to the source of the transistor M7, the drain of the transistor M4, and one end of the capacitor C1, and the transistors M3, M4, M5, M6 The source of , and one end of the capacitors C0, C1, C2 are all connected to the connection point A.

The soft drive circuit module includes a level conversion module and a trigger. The two drive output terminals of the level conversion module are respectively connected to the R and S pins of the trigger input terminal, and the Q pins of the trigger output terminal are respectively connected to transistors M1, M3, and M5. The gate of the flip-flop output, the QN pin of the flip-flop output terminal is respectively connected to the gates of transistors M6 and M9 and the anode of the inverter CD, VDD is connected to the source of transistor M1 and the drain of transistor M4, and the drain of transistor M1 is connected to transistor M2 The source of the transistor M2 is divided into three ways to connect the drains of the transistors M3 and M5 and the gate of the transistor M4 respectively, the sources of the transistors M3 and M5 are grounded, and the source of the transistor M4 is respectively connected to the drains of the transistors M7 and M8 pole and one end of the resistor R1, the negative pole of the inverter CD is respectively connected to the gates of the transistors M7 and M8 and the drain of the transistor M6, the source of the transistor M6 is connected to VDD, the other end of the resistor R1 is connected to one end of the resistor R2, and the transistor M3 , M5, M7, M8 sources and the other end of resistor R2 are grounded, the sources of transistors M9, M10, M11, M12 are connected to VDD, the gate-drain of transistor M12 is short-circuited, and the drains of transistor M12 are connected to transistors in two ways The drains of M19 and M13, the gate-drain of the transistor M11 are short-circuited, the drain of the transistor M11 is connected to the drain of the transistor M18, the gate of the transistor M11 is connected to the gate of the transistor M10, and the drain of the transistor M10 is divided into four ways respectively The drains of the transistors M15 and M16 are connected to the gates of the transistors M14 and M15, the drain of the transistor M9 is divided into two paths and respectively connected to the drain of the transistor M17 and the positive pole of the inverter CE, and the negative pole of the inverter CE is connected to the gate of the transistor M13 The gate and the source of M13 are connected to the drain of the transistor M14, the negative pole of the current source DC is connected to VDD, and the positive pole of the current source DC is divided into four ways to respectively connect the drain of the transistor M20 and the gates of the transistors M18, M19, and M20, and the transistor M17 The gate of the transistor M16 is connected to the feedback voltage VFB, the gate of the transistor M16 is connected to the voltage UP, and the sources of the transistors M20, M19, M18, M17, M16, M15, and M14 are all grounded.

The level conversion circuit module includes transistors M1, M2, M3, M4 and an inverter CB. The signal Driver-logic is respectively connected to the positive pole of the inverter CB and the gate of the transistor M2, and the negative pole of the inverter CB is connected to the gate of the transistor M3. Gate, VCC is connected to the sources of transistors M1 and M4, the sources of transistors M2 and M3 are grounded, the gate of transistor M1, the drains of transistors M3 and M4 are connected to the DOWN terminal, the gate of transistor M4, the transistors M1 and M2 The drains of each are connected to the UP terminal, the UP terminal and the DOWN terminal are the drive signal output terminals of the level conversion circuit module, and the signal Driver-logic is the drive control signal.

The chip realizes a new type of constant current control mode by detecting the demagnetization time to adjust the system operating frequency. The sampling circuit module selects the 2/3 point of the demagnetization time interval of the auxiliary winding as the sampling point of the feedback voltage, and then passes the error amplifier and The error amplification of the threshold reference is designed, and the soft drive design includes a level conversion module, a soft drive module and a gate drive module with a totem pole structure, which are used to reduce switching EMI interference and improve efficiency.

Compared with the prior art, the present invention proposes a high-precision constant current and constant voltage chip design, which greatly improves the precision of output voltage and output current. At the same time, the system has high overall efficiency and stability, and the coordination and cooperation of the modules in the chip make the chip have high working performance.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a structural schematic diagram of a flyback transformer;

Fig. 3 is the schematic diagram of the circuit structure of the sampling circuit module;

Fig. 4 is a schematic structural diagram of a level conversion circuit module;

Fig. 5 is a schematic diagram of the structure of the soft driving circuit module.

detailed description

In order to make the objects and advantages of the present invention clearer, the present invention will be specifically described below in conjunction with examples. It should be understood that the following words are only used to describe one or several specific implementation modes of the present invention, and do not strictly limit the protection scope of the specific claims of the present invention.

For modules not described in detail in the present invention, those skilled in the art can implement them according to the means adopted by chips in the prior art.

The technical scheme adopted by the present invention is shown in Figure 1, a high-precision PSR constant current constant voltage AC/DC chip, including a PSR flyback transformer, a constant current loop module, a constant voltage loop module, a control circuit module, a sampling Keep modules such as circuit modules and soft drives. The PSR feedback control system uses the relationship between the feedback voltage of the auxiliary coil winding and the output voltage to sample the output voltage by adding an auxiliary coil winding, and cooperates with the constant current/constant voltage control loop in the chip to make the output have higher accuracy. At the same time, the slow soft start process of the soft drive ensures EMI, and the fast shutdown design ensures work efficiency.

Fig. 2 is a flyback transformer, Controller is the control chip to be designed in the present invention, the control chip has three pins of G, FB, and CS, and the CS pin collects external circuit information so as to feed back to the current-limiting comparator to determine the switching of the power tube The FB pin feeds back to the chip the information indicating the output voltage change after the resistor divider. Finally, the external power tube M0 is controlled from the G pin. The capacitor C0 and the resistor R3 are connected in parallel. The drain of the transistor M0, one end of the primary winding NP is connected to the absorbing circuit, the other end is connected to the drain of the transistor M0, the gate of the power transistor M0 is connected to the G pin of the control chip, the source is connected to the CS interface of the control chip, and one end of the resistor RS Connect the source of the transistor M0, the other end is connected to the external signal, one end of the secondary winding NS is connected to the positive pole of the diode D0, the other end is connected to the capacitor C0, the negative pole of D0 is connected to one end of the capacitor C0, the resistor R0 and the capacitor C0 are connected in parallel, and the winding NAUX is connected to the resistor RS The other end of R1 is connected to resistor R1, the other end of R1 is connected to resistor R2, the other end of R2 is connected to resistor RS, and the middle point between R1 and resistor R2 is connected to the FB end of the control chip.

Figure 3 is a structural diagram of the sampling circuit, SH is the sampling information output terminal, VDD is connected to the source of the transistor Vbias, the drain of Vbias is connected to the source of the transistor M9, the drain of the transistor M9 is connected to the non-inverting terminal of the operational amplifier CA, and the transistor M1 The drain of the transistor M9 is connected to the drain of the transistor M9, its source is connected to the drain of the transistor M3 and one end of the capacitor C0, the source of the transistor M3 is connected to the other end of the capacitor C0, and the drain of the transistor M2 is connected to the drain of the transistor M9 and CA The non-inverting terminal of the transistor M7, its source is connected to the source of the transistor M7 and the drain of the transistor M4, the source of the transistor M4 is connected to one end of the capacitor C1 and the capacitor C0, the other end of the capacitor C1 is connected to the drain of the transistor M4, and the source of the transistor M8 The pole is connected to the source of M1, and its drain is connected to the inverting terminal of the operational amplifier CA, and the CA inverting terminal is also connected to the drain of the transistor M7 and the drains of the transistors M5 and M6, and the sources of the transistors M5 and M6 are connected to the transistors M3 and The source of M4 and the two ends of the capacitor C2 are respectively connected to the source and drain of the transistors M5 and M6.

Figure 4 is a structural diagram of the level conversion circuit module, the UP terminal and the DOWN terminal are the drive signal output terminals of the module, Driver-logic is the drive control signal, VCC is connected to the sources of transistors M1 and M4, and the gate of transistor M1 is connected to the transistor The drain and output of M3 are down, the drain of M1 is connected to the drain of transistor M2 and output up, the gate of transistor M4 is connected to the drain of M2, its source is connected to the drain of transistor M3, and the gate of transistor M2 is reversed The positive pole of the phase converter CB is connected to the input signal terminal, the negative pole of the inverter CB is connected to the gate of the transistor M3, and the sources of the transistors M2 and M3 are grounded.

Figure 5 is a structural diagram of the soft drive circuit, the Driver module is the level conversion module in Figure 4, its two drive output terminals are connected to the R and S pins of the RS flip-flop, the source of the transistor M1 and the drain of the transistor M4 are connected to VDD and VFB are feedback voltages, the gate of transistor M1 is connected to the Q terminal of the RS flip-flop, the drain is connected to the source of transistor M2, the drain of M2 is connected to the drains of transistors M3 and M5, and the gates of transistors M3 and M5 are connected Trigger Q terminal, its source is grounded, the gate of transistor M4 is connected to the drain of M2, its source is connected to the drains of transistors M7 and M8, the drain of transistor M7 is connected to one end of resistor R1, and the other end of resistor R1 is connected to resistor R2 One end is connected, the sources of transistors M7 and M8 and one end of resistor R2 are grounded, the gates of transistors M7 and M8 are connected to the negative pole of the inverter CD, the positive pole of the inverter is connected to the QN terminal of the RS flip-flop, and the source of transistor M6 Connect to VDD, connect the gate to QN, connect the drain to the negative pole of the inverter CD, connect the positive pole of the inverter CD to the gate of the transistor M9, connect the sources of the transistors M9, M10, M11, and M12 to VDD, and connect the gate to the drain of the transistor M12 The drain is connected to the drain of the transistor M19, the gate of the transistor M19 is connected to the gate of the transistor M20 and the positive pole of the current source DC, the drain of the transistor M20 is connected to the positive pole of the current source DC, and the transistors M20, M19, M18, M17 , M16, M15, M14's sources are grounded, the gate-drain of transistor M11 is short-circuited and connected to the drain of transistor M18, the gate of transistor M18 is connected to the positive pole of current source DC, and the gate of transistor M10 is connected to the gate of transistor M11 , the drain of which is connected to the drain of transistor M16, the drain of transistor M9 is connected to the anode of inverter CE and the drain of transistor M17, the cathode of inverter CE is connected to the gate of transistor M13, and the drain of M13 is connected to transistor M12 The drain of the transistor M15 has its source connected to the drain of the transistor M14, the gates of the transistors M14 and M15 are connected to the drain of the transistor M10, and the drain of the transistor M15 is connected to the drains of the transistors M10 and M16.

In a word, the present invention can effectively reduce the cost and simplify the system design, improve the inherent defects of PSR technology at the same time, realize higher constant current accuracy and output voltage accuracy, and finally realize a high-efficiency Constant current constant voltage control chip. The above is only a preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, after knowing the content recorded in the present invention, they can also make changes to it without departing from the principle of the present invention. Several equivalent transformations and substitutions should also be deemed to belong to the protection scope of the present invention.

Claims (6)

1. a PSR constant current constant voltage AC/DC chip, it is characterised in that: include control chip and PSR flyback transformer, control chip includes software-driven modules, constant current loop module, constant voltage Loop module, soft-sphere model module, PSR flyback transformer is by feedback circuit module and constant current ring Road module is connected, and SR flyback transformer is connected with constant voltage loop module by sample circuit module Connecing, constant current loop module is connected with soft-sphere model module respectively with the outfan of constant voltage loop module.

PSR constant current constant voltage AC/DC chip the most according to claim 1, it is characterised in that: PSR flyback transformer includes being made up of winding NAUX, primary side winding NP, secondary limit winding NS Ancillary coil winding and diode D0, D1；The negative pole of diode D1 divides two-way to connect electricity respectively Holding one end and resistance R3 one end of C0, positive pole and primary side winding NP one end of diode D1 all connect Enter the drain electrode of power transistor M0, electric capacity C0, resistance R3 and the other end of primary side winding NP All being connected with absorbing circuit, the grid of power transistor M0 connects the G pin of control chip, The source electrode of power transistor M0 divides CS pin that two-way connects control chip respectively and resistance RS's One end, winding NAUX one end connects one end of resistance R1, the other end of resistance R1 and resistance R2 One end be connected, the FB pin of the contact Access Control chip between resistance R1, R2, resistance RS, resistance R2, the other end of winding NAUX all access outer signal；One end of secondary limit winding NS Connect the positive pole of diode D0, diode D0 negative pole divide one end that two-way connects electric capacity C1 respectively, One end of resistance R0, electric capacity C1, resistance R0 the other end all with the other end of time limit winding NS It is connected.Wherein: CS pin is used for gathering external circuit information and feeds back to Current-Limiting Comparator decision power The shutoff of pipe, FB pin is for feeding back the expression output voltage after electric resistance partial pressure to control chip The information of change, G pin is for controlling the power tube M0 of outside.

PSR constant current constant voltage AC/DC chip the most according to claim 1, it is characterised in that: Sample circuit module includes transistor Vbias, operational amplifier CA, and VDD connects transistor Vbias Source electrode, transistor Vbias drain electrode connect transistor M9 source electrode, operational amplifier CA's In-phase end connects the drain electrode of transistor M9, M1, M2 respectively, and the end of oppisite phase of operational amplifier CA divides Lian Jie the drain electrode of transistor M5, M6, M7, M8 and one end of electric capacity C2, operational amplifier The outfan of CA connects sample information outfan SH, and the source electrode of transistor M1 divides three tunnels to connect respectively The drain electrode of transistor M3, one end of electric capacity C0, the source electrode of transistor M8, the source of transistor M2 Ji Fen tri-tunnel connects the source electrode of transistor M7, the drain electrode of transistor M4 and electric capacity C1's respectively One end, the source electrode of transistor M3, M4, M5, M6 and one end of electric capacity C0, C1, C2 all with Junction point A is connected.

PSR constant current constant voltage AC/DC chip the most according to claim 1, it is characterised in that: Soft-sphere model circuit module includes level switch module, trigger, two drivings of level switch module Outfan connects R, S pin of trigger input respectively, and the Q pin of trigger outfan divides Not Lian Jie the grid of transistor M1, M3, M5, the QN pin of trigger outfan connects crystalline substance respectively The grid of body pipe M6, M9 and the positive pole of phase inverter CD, VDD connect transistor M1 source electrode and The drain electrode of transistor M4, the drain electrode of transistor M1 connects the source electrode of transistor M2, transistor M2 Drain electrode point three tunnels connect drain electrode and the grid of transistor M4 of transistor M3, M5 respectively, brilliant The source ground of body pipe M3, M5, the source electrode of transistor M4 connects transistor M7, M8 respectively Drain electrode and one end of resistance R1, the negative pole of phase inverter CD connects transistor M7, M8 respectively Grid and the drain electrode of transistor M6, the source electrode of transistor M6 connects VDD, the other end of resistance R1 Connect the another of one end of resistance R2, the source electrode of transistor M3, M5, M7, M8 and resistance R2 The equal ground connection in one end, the source electrode of transistor M9, M10, M11, M12 meets VDD, transistor M12's Grid leak short circuit, transistor M12 drain electrode point two-way connects the drain electrode of transistor M19, M13 respectively, The grid leak short circuit of transistor M11, the drain electrode of transistor M11 is connected with the drain electrode of transistor M18, The grid of transistor M11 is connected with the grid of transistor M10, and the drain electrode of transistor M10 divides four tunnels Connect drain electrode and the grid of transistor M14, M15, the transistor of transistor M15, M16 respectively The drain electrode point two-way of M9 connects drain electrode and the positive pole of phase inverter CE of transistor M17 respectively, anti-phase The negative pole of device CE connects the grid of transistor M13, and the source electrode of M13 connects the drain electrode of transistor M14, The negative pole of current source DC connects VDD, and the positive pole of current source DC divides four tunnels to connect transistor M20 respectively Drain electrode and the grid of transistor M18, M19, M20, the grid of transistor M17 connects feedback The grid of voltage VFB, transistor M16 connect voltage UP, transistor M20, M19, M18, M17, The source grounding of M16, M15, M14.

PSR constant current constant voltage AC/DC chip the most according to claim 1, it is characterised in that: Level shifting circuit module includes transistor M1, M2, M3, M4 and phase inverter CB, signal Driver-logic is respectively connected to positive pole and the grid of transistor M2, the phase inverter of phase inverter CB The negative pole of CB connects the grid of transistor M3, and VCC connects the source electrode of transistor M1, M4, crystal The source ground of pipe M2, M3, transistor M1 grid, transistor M3, M4 drain electrode all and DOWN End is connected, and transistor M4 grid, the drain electrode of transistor M1, M2 are all connected with UP end, UP End, DOWN end are the driving signal output part of this level shifting circuit module, signal Driver-logic is drive control signal.

PSR constant current constant voltage AC/DC chip the most according to claim 1, it is characterised in that: Also include over-and under-voltage module, overheat protector module and oscillator module.