CN100514827C - Control device of equal ratio driving type power supply - Google Patents

Abstract

The invention relates to a control device of an equal ratio driving type power supply, which comprises a feedback control circuit for providing feedback control of the power supply. The soft start input end is used for setting the soft start time of the power supply. The first output end and the second output end are used for outputting a first output signal and a second output signal to couple and drive a first change-over switch and a second change-over switch of the power supply so as to control the output of the power supply. A protection unit has a voltage input terminal, a current detection terminal, a power detection terminal and a signal detection terminal. The signal detection terminal is used for detecting the voltage level of the transformer signal. The input end of the power switch receives a power switch signal for turning on and off the power supply. The power status indication terminal generates a power status signal for indicating the output status of the power supply.

Description

Control device for proportional drive power supply

technical field

The invention relates to a control device of a power supply, in particular to a control device of an proportional driving power supply.

Background technique

The advantage of the proportional driving power supply circuit is high efficiency, especially when driving a bipolar transistor, its control device does not need to generate a large base current to drive the bipolar transistor. The control device only needs to generate a small control signal to drive and control a high-watt power output.

Figure 1 is a circuit of a ratio-driven power supply. A first output signal S ₁ and a second output signal S ₂ generated by the control device (not shown in the figure) are used to control the driving transistors 51 and 61 respectively. The driving transistors 51 and 61 are connected to a driving transformer 20 to control switching of the power transistors 50 and 60 . The power transistors 50 , 60 and the capacitors 40 , 45 form a half-bridge driving circuit for switching a transformer 10 . The transformer 10 has multiple sets of secondary windings (such as windings N _S1 , N _S1 ′, _NS2 , and _NS2 ′), through rectifiers (such as diodes 71-74), inductors (such as inductors 91, 95) and capacitors ( For example, rectification and filtering by capacitors 81 and 83 ) respectively generate multiple sets of voltages (such as voltages E ₁ and E ₂ ). The voltages E ₁ and E ₂ can be filtered by multiple resistors (such as impedances 92, 93, 96) and capacitors (such as capacitors 82, 84, 85) to generate more sets of output voltages (such as output voltage V ₁ , V _2A , V _2B ). The resistors 92, 93, 96 can be inductors or resistors. The voltage E ₁ can be passed through a voltage regulator 100 to generate another output voltage V ₃ . In addition, the secondary windings N _S1 and N _S1 ′ of the transformer 10 are connected to a signal detection terminal UVAC through a rectifier 73, 74 and a voltage divider circuit composed of resistors 98, 99 for detecting the signal of the transformer 10. voltage level.

The drive transformer 20 shown in FIG. 1 includes push-pull windings _ND1 and _ND2 , base windings N _B1 and N _B2 , and a current winding N _I . The center taps of the push-pull windings _ND1 and _ND2 are coupled to a power supply V _CC through a diode 31 and a resistor 34 . The center tap is coupled to a power detection terminal OPP through a diode 32, a capacitor 33 and resistors 35, 36 for detecting the output power of the proportional driving power supply. In addition, both ends of the push-pull windings _ND1 and _ND2 are respectively connected to the driving transistors 51 and 61 . The driving transistors 51 and 61 respectively have reverse diodes 52 and 62 connected in parallel with them. The base windings _NB1 and _NB2 of the driving transformer 20 drive the power transistors 50 and 60 through the impedance circuits 55 and 65 respectively. The current winding N _I is connected in series with the half-bridge driving structure circuit for sensing the current of the transformer 10 .

2A-2F respectively illustrate the working sequence and state of the equal-ratio driving power supply. As shown in FIG. 2A, when the transistor 51 is turned on by the first output signal _S1 and the transistor 61 is turned off by the second output signal _S2 , a small current will flow Through the resistor 34 , the diode 31 , the push-pull winding N _D1 and the driving transistor 51 . Furthermore, the push-pull winding _ND1 will induce an electromotive force in the base winding N _B1 , and the electromotive force will push the power transistor 50 through the impedance circuit 55 .

Once the power transistor 50 is turned on, as shown in FIG. 2B , a current _IP will flow from the capacitor 40 through the power transistor 50 , the current winding N _I , the transformer 10 and back to the capacitor 40 . At this time, the current winding N _I will generate and amplify a proportional current I _B1 in the base winding N _B1 due to the self-excited positive feedback effect,

I _B1 ＝I _P ×(T _NI /T _NB1 )---------------------- (1)

Where T _NI and T _NB1 are the number of turns of the current winding N _I and the base winding N _B1 respectively.

From formula (1), it can be seen that the ratio of the base current to the collector current of the power transistor 50 can be determined by the winding ratio of the current winding N _I and the base winding N _B1 of the driving transformer 20 . When the current I _B1 pushes the base of the power transistor 50 through the impedance circuit 55, a voltage V _B will be established on the base winding N _B1 ,

V _B ＝ I _B1 × Z ₅₅ ----------------------------- (2)

Where Z ₅₅ is the equivalent impedance of the impedance circuit 55 .

This voltage V _B will induce a voltage V _D in the push-pull winding _ND1 ,

V _D ＝(T _ND1 /T _NB1 )×V _B --------------------- (3)

Where T _ND1 is the number of turns of the push-pull winding _ND1 .

From formula (1), (2) and formula (3), we can know

V _D ＝(T _ND1 /T _NB1 )×(T _NI /T _NB1 )×Z ₅₅ ×I _P ----- (4)

Therefore, it can be known from formula (3) that the voltage V _D changes in proportion to the current I _P of the transformer 10 . The voltage V _D is coupled to the power detection terminal OPP through the diode 32 , the capacitor 33 and the resistors 35 and 36 for detecting the output power of the power supply.

Please refer to FIG. 2C, when the first output signal _S1 driving transistor 51 is turned on and the second output signal _S2 driving transistor 61 is turned on, a low impedance will be formed at both ends of the push-pull winding _ND1 and _ND2 , making it Like a short circuit. Because the push-pull windings N _D1 and N _D2 are short-circuited, the energy cannot be transferred to the base windings N _B1 and N _B2 . At this time, the base windings N _B1 and N _B2 are also induced into a low impedance state. Therefore, power transistors 50 and 60 are turned off.

Please refer to FIG. 2D-FIG. 2F, which respectively illustrate the operation of the other phase of the proportional driving power supply. The working sequence and state are similar to those in FIG. 2A-FIG. 2C, so no further description is given.

From the above, it can be seen that when the proportional driving power supply drives the power transistors 50 and 60 , it uses the self-excited positive feedback of the driving transformer 20 to complete, and turns off the power transistors 50 and 60 by short-circuiting the driving transformer 20 . The information of the current I _P is also rectified and filtered by the diode 32 and the capacitor 33 to become a DC signal before being sent to the power detection terminal OPP. Therefore, cycle-by-cycle control and protection cannot be achieved. When the output of the ratio-driven power supply is short-circuited, due to the self-excited positive feedback effect of the drive transformer 20, a very large current output will be generated, and the ratio-driven power supply and its supplied power supply will be burned. system. The maximum current limit of each group output of the ratio-driven power supply can be used to protect the power supply and the system it supplies, especially to protect the associated connectors and related joints. In addition, the power switch function designed for energy saving and power management is a necessary control circuit for proportional drive power supplies.

Contents of the invention

The purpose of the present invention is to provide a complete control and protection circuit of the proportional drive power supply with a new structure, and the technical problem to be solved is to make this high-efficiency, low-cost proportional drive power supply circuit It has practicality, so it is more suitable for practical use.

Another object of the present invention is to provide a control device for a proportional drive power supply, the technical problem to be solved is to control and protect the output of the proportional drive power supply with high efficiency and low cost, And the output status of the power supply can be indicated by the power status signal, which is more suitable for practical use.

Another object of the present invention is to provide a control device for a power supply. The technical problem to be solved is to control the output of the power supply with high efficiency and low cost, so that it is more suitable for practical use.

Another object of the present invention is to provide a control device for a power supply. The technical problem to be solved is to control and protect the output of the power supply with high efficiency and low cost, and to control and protect the output of the power supply through the power supply status signal. Indicating the output status of the power supply is more suitable for practical use and has industrial utilization value.

Based on the above and other objectives, the present invention proposes a control device for a proportional drive power supply, including a first feedback input terminal, a first amplifier output terminal, a soft start input terminal, and an oscillation frequency setting terminal , at least one voltage input terminal, at least one current detection terminal, a power detection terminal, a signal detection terminal, a power switch input terminal, a power status indicator terminal, a first output terminal, a second output terminal, A first amplifier, an oscillator, a protection unit and an output circuit. The first feedback input terminal is coupled to the output of the proportional driving power supply to provide a first set of feedback control of the proportional driving power supply. Feedback compensation is provided at the output terminal of the first amplifier. The soft-start input terminal is connected to a soft-start capacitor to set the soft-start time of the constant ratio drive power supply. The oscillation frequency setting end is connected to a resistor. The voltage input terminal, the current detection terminal and the power detection terminal are coupled to the proportional driving power supply. The signal detection end is coupled to the transformer of the proportional driving power supply. The first output terminal outputs a first output signal to the first switching switch of the proportional driving power supply. The second output end outputs a second output signal to the second switching switch of the proportional driving power supply. Wherein, the first switching switch is connected with the second switching switch to switch the transformer of the proportional driving power supply, and then control the output of the proportional driving power supply.

The first input of the first amplifier is connected to the first feedback input, the second input of the first amplifier is coupled to the soft-start input, and the output of the first amplifier is coupled to the first amplifier output, wherein the soft-start input provides The first amplifier-reference voltage. The oscillator is connected to the oscillation frequency setting terminal for setting its oscillation frequency according to the resistance. The protection unit is used to connect to the voltage input terminal to detect the output voltage of the proportional driving power supply, and to connect to the current detection terminal to cooperate with the voltage input terminal to detect the output current of the proportional driving power supply, and to connect to The power detection terminal is used to detect the output power of the proportional driving power supply, connected to the signal detection terminal to detect the voltage level of the signal of the transformer, and connected to the power switch input terminal to receive a power switch signal. The output circuit is electrically connected to the first amplifier, the oscillator, the protection unit, the first output terminal and the second output terminal, and is used to generate and provide the first output signal and the second output signal to the first amplifier according to the output of the first amplifier respectively. The first output terminal and the second output terminal determine the switching frequency of the first output signal and the second output signal according to the output of the oscillator, and determine the switching frequency of the proportional driving power supply according to the output of the protection unit. Wherein, the control device outputs a power state signal through the power state indication end according to the voltage input end, the signal detection end and the power switch input end to indicate the output state of the proportional driving power supply.

From another point of view, the present invention proposes a control device for proportional driving power supply, which includes a first feedback input terminal, a first amplifier output terminal, a soft start input terminal, and a first output terminal , a second output terminal, at least one voltage input terminal, a power detection terminal, a signal detection terminal, a power switch input terminal and a power supply status indication terminal. The first feedback input is connected to the first input of the first amplifier, wherein the first feedback input is further coupled to the output of the proportional-driven power supply to provide a first set of proportional-driven power supplies Feedback control. The first amplifier output terminal is coupled to the output of the first amplifier to provide feedback compensation. The soft-start input terminal is connected to the soft-start capacitor, and is used to set the soft-start time of the proportional drive power supply. The soft-start input terminal is further coupled to the second input of the first amplifier to provide a reference voltage for the first amplifier. The first output terminal and the second output terminal respectively output a first output signal and a second output signal. The first output signal and the second output signal are generated according to the output of the first amplifier, and are coupled to drive the first switch and the second switch. Wherein, the first switching switch is connected with the second switching switch to switch the transformer of the proportional driving power supply, and then control the output of the proportional driving power supply. The voltage input end is connected to the over-voltage protection circuit and the low-voltage protection circuit, and is used for detecting the output voltage of the proportional driving power supply. The power detection terminal is connected to the over-power protection circuit for detecting the output power of the proportional drive power supply. The signal detection end is coupled to the transformer and the signal detection circuit for detecting the voltage level of the signal of the transformer. The power switch input end receives the power switch signal and is connected to the power switch circuit for turning on and off the proportional driving power supply. The power status indication terminal generates a power status signal according to the output of the voltage protection circuit, the output of the signal detection circuit and the power switch signal, and is used to indicate the output status of the proportional driving power supply.

The present invention proposes a control device for a power supply, including a first feedback input terminal, a first amplifier output terminal, a soft start input terminal, a first output terminal, a second output terminal and a power switch input end. The first feedback input terminal is connected to the first input of the first amplifier, wherein the first feedback input terminal is further coupled to the output of the power supply to provide a first set of feedback control of the power supply. The first amplifier output terminal is coupled to the output of the first amplifier to provide feedback compensation. The soft-start input terminal is connected to the soft-start capacitor and is used to set the soft-start time of the power supply. The soft-start input terminal is further coupled to the second input of the first amplifier to provide a reference voltage for the first amplifier. The first output terminal and the second output terminal respectively output a first output signal and a second output signal. The first output signal and the second output signal are generated according to the output of the first amplifier, and are coupled to drive the first switch and the second switch. Wherein, the first switching switch is connected with the second switching switch and switches the transformer of the power supply, thereby controlling the output of the power supply. The power switch input end receives the power switch signal and is connected to the power switch circuit for turning on and off the power supply.

The present invention further proposes a control device for a power supply, including a voltage input terminal, a current detection terminal, a power detection terminal, a signal detection terminal, a power switch input terminal, a power status indicator terminal and a power protection output. The voltage input terminal is connected to the over-voltage protection circuit and the low-voltage protection circuit for detecting the over-voltage state and the low-voltage state of the output voltage of the power supply. The current detection terminal cooperates with its voltage input terminal and is connected to the overcurrent protection circuit for detecting the overcurrent state of the output current of the power supply. The power detection terminal is connected to the over-power protection circuit for detecting the output power of the power supply. The signal detection terminal is coupled to the transformer of the power supply and the signal detection circuit for detecting the voltage level of the signal of the transformer. The power switch input end receives the power switch signal and is connected to the power switch circuit for turning on and off the power supply. The power status indication terminal generates a power status signal to indicate the output status of the power supply according to the output of the overvoltage protection circuit and the low voltage protection circuit, the output of the signal detection circuit and the power switch signal. The power protection output terminal generates a power protection signal according to the overvoltage protection circuit, the low voltage protection circuit, the overcurrent protection circuit and the overpower protection circuit for turning on and off the power supply.

Because the present invention provides a complete control and protection circuit of the proportional drive power supply, it can control the output of the proportional drive power supply with high efficiency and low cost, and protect the proportional drive power supply and its load circuit , and can indicate the output status of the power supply through the power status signal.

It can be seen from the above that the present invention relates to a control device for a proportional driving power supply, which includes a feedback control circuit for providing feedback control of the power supply. The soft start input terminal is used to set the soft start time of the power supply. The first output terminal and the second output terminal are used to output the first output signal and the second output signal to couple and drive a first switching switch and a second switching switch of the power supply to control the output of the power supply. A protection unit has a voltage input terminal, a current detection terminal, a power detection terminal and a signal detection terminal. The signal detection terminal is used to detect the voltage level of the transformer signal. The power switch input end receives a power switch signal for turning on and off the power supply. The power status indication terminal generates a power status signal for indicating the output status of the power supply.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited below, and are described in detail as follows in conjunction with the accompanying drawings.

Description of drawings

Figure 1 shows the circuit of a general proportional drive power supply.

2A-2F respectively illustrate the working sequence and state of the proportional driving power supply in FIG. 1 .

FIG. 3 illustrates a control device of a proportional driving power supply according to the present invention.

FIG. 4 illustrates a voltage regulator according to the present invention.

FIG. 5 illustrates an oscillator according to the present invention.

FIG. 6 illustrates a protection unit according to the present invention.

Figure 7 illustrates a soft start circuit according to the present invention.

FIG. 8 illustrates an overvoltage protection circuit according to the present invention.

FIG. 9 illustrates a low voltage protection circuit according to the present invention.

FIG. 10 illustrates an overcurrent protection circuit according to the present invention.

FIG. 11 illustrates an overpower protection circuit according to the present invention.

FIG. 12 illustrates an interface circuit according to the present invention.

10, 20: Transformer

31, 32, 52, 62, 71~74: Diodes

33, 40, 45, 81～85, 126, 225, 450: capacitance

34～36, 55, 65, 92, 93, 96, 98, 99, 121～123, 125, 205, 515～519, 525～529, 535, 537: Impedance

50, 51, 60, 61, 110, 163, 211～217, 380: Transistor

91, 95: Inductance

100: voltage regulator

128: Controllable unit

151, 152, 370, 578: Flip-flops

156, 157, 240, 245, 375, 376: reverse and gate

158, 585: and gate

159, 250, 371, 583, 584, 586: inverter

160, 162, 210, 430: amplifier

165, 230, 235, 512~514, 522~524, 532~534, 562, 563, 571, 572: Comparator

220 oscillator 221, 222: switch

300: Protection unit 310: Overvoltage protection circuit

320: Over-current protection circuit 330: Over-power protection circuit

340: Interface circuit 350: Low voltage protection circuit

361, 587: Inverse OR gate 362, 511, 521, 531: OR gate

365, 366, 510, 520, 530, 560, 581: delay circuit

410, 420, 538～539: current source 575, 576: bounce circuit

COM: first amplifier output terminal e _n ~ e ₁ : current detection terminal

IN: The first feedback input terminal FB: The second feedback input terminal

OPH: Over-power protection signal OPP: Power detection terminal

OVP: Over-voltage protection signal PG: Power status indicator terminal

PLS: Oscillating signal PSON: Power switch input terminal

RI: Oscillation frequency setting terminal OUT1: The first output terminal

OUT2: Second output terminal S ₁ : First output signal

S ₂ : Second output signal SS: Soft start input terminal

UVAC: signal detection terminal UVP: low voltage protection signal

VA: output terminal of the second amplifier V _n ～V ₁ : voltage input terminal

V _REF : Reference voltage V _R0 ~ V _R7 : Reference level

V _SAW : sawtooth wave signal V _H and V _L : clamp voltage

Detailed ways

In order to further explain the technical means and effects adopted by the present invention to achieve the intended purpose of the invention, the specific implementation manner, Structure, characteristic and effect thereof are as follows in detail.

To facilitate the description of the application of the present invention, the following embodiments still use the proportional driving power supply in FIG. 1 as the control target of the control device in the embodiments of the present invention. Those skilled in the art can uphold the spirit of the present invention and the teachings of the following embodiments, and deduce it to other power supplies by analogy.

FIG. 3 illustrates an embodiment of a control device of a proportional driving power supply according to the present invention. Please refer to FIG. 3 , the control device of the ratio-driven power supply (hereinafter referred to as the power supply) includes a first feedback input terminal IN, a first amplifier output terminal COM, a soft-start input terminal SS, Oscillation frequency setting terminal RI, voltage input terminal V _n ~ V ₁ , current detection terminal e _n ~ e ₁ , power detection terminal OPP, signal detection terminal UVAC, power switch input terminal PSON, power status indicator terminal PG, The first output terminal OUT1 , the second output terminal OUT2 , the first amplifier 160 , the oscillator 200 , the protection unit 300 and the output circuit. In this embodiment, the output circuit includes a T-type flip-flop 151 , a D-type flip-flop 152 , NAND gates 156 and 157 , an AND gate 158 , an inverter 159 , a comparator 165 and so on.

The first feedback input terminal IN is connected to the first input (the negative input here) of the first amplifier 160 . The first feedback input terminal IN is further coupled to the output of the power supply for providing a first set of feedback control of the power supply. The first amplifier output terminal COM is coupled to the output of the first amplifier 160 to provide feedback stability compensation. The soft-start circuit 400 is connected to a soft-start capacitor 450 (shown in FIG. 7 ) via a soft-start input terminal SS for setting a soft-start time of the power supply. The soft-start input SS is further coupled to the second input (positive input here) of the first amplifier 160 to provide the first amplifier with a reference voltage V _REF . The output circuit outputs a first output signal S 1 and a second output signal S ₂ through the first output terminal OUT1 and the second output terminal _OUT2 according to the output of the first amplifier 160 to couple and drive the first switch in the power supply The switch 50 and the second toggle switch 60 . The first switching switch 50 and the second switching switch 60 are connected to the transformer 10 of the power supply to control the output of the power supply.

The voltage input terminals V _n ˜V ₁ , the current detection terminals e _n ˜e ₁ and the power detection terminal OPP are coupled to the power supply. The signal detection terminal UVAC is coupled to the transformer 10 of the power supply. The protection unit 300 is connected to the voltage input terminals V _n ˜V ₁ (that is, the output of the power supply) to detect the output voltage of the power supply. The protection unit 300 is also connected to the current detection terminals e _n ˜e ₁ to cooperate with the voltage input terminals V _n ˜V ₁ to detect the output current of the power supply. The protection unit 300 detects the output power of the power supply through the power detection terminal OPP, and outputs an over-power protection signal OPH according to the detection result. The protection unit 300 is also connected to the signal detection terminal UVAC to detect the voltage level of the signal of the transformer 10 . In addition, the protection unit 300 receives a power switch signal through the power switch input terminal PSON, and outputs a shutdown signal OFF accordingly. The output circuit further determines to turn on and off the power supply according to the output of the protection unit 300 .

Wherein, the control device in FIG. 3 outputs a power status signal through the power status indication terminal PG according to the voltage input terminals V _n ˜V ₁ , the signal detection terminal UVAC and the power switch input terminal PSON to indicate the output of the power supply. situation.

The oscillator 200 generates an oscillation signal PLS and a sawtooth signal V _SAW . The oscillator 200 is connected to the resistor 205 (shown in FIG. 5 ) through the oscillation frequency setting terminal RI so as to determine its oscillation frequency according to the resistor 205 . The oscillation signal PLS is connected to trigger inputs of the T-type flip-flop 151 and the D-type flip-flop 152 . The sawtooth signal V _SAW is coupled to a first input (here, the negative input) of the comparator 165 . A second input (here the positive input) of comparator 165 is coupled to the output of first amplifier 160 . The comparator 165 compares the sawtooth signal V _SAW with the output of the first amplifier 160 and then outputs a pulse modulated signal. The output of comparator 165 is connected to an input of AND gate 158 . The other input of AND gate 158 is coupled through inverter 159 to shutdown signal OFF. The output of AND gate 158 is used to reset the output of D-type flip-flop 152 .

The NAND gates 156 and 157 output the first output signal _S1 and the second output signal _S2 to the first output terminal OUT1 and the second output terminal OUT2 respectively. The inputs of the NAND gate 156 are the oscillation signal PLS, the overpower protection signal OPH, the first output of the T-type flip-flop 151 and the first output of the D-type flip-flop 152 respectively. The inputs of the NAND gate 157 are the oscillation signal PLS, the overpower protection signal OPH, the second output of the T-type flip-flop 151 and the first output of the D-type flip-flop 152 . Therefore, the output circuit can determine the switching frequency of the first output signal S ₁ and the second output signal S ₂ according to the output of the oscillator 200 .

In addition, the control device in FIG. 3 further includes a second feedback input terminal FB, a controllable unit 128 and a second amplifier output terminal VA. The controllable unit 128 includes a second amplifier 162 and a transistor 163 . The second feedback input terminal FB is connected to an input (positive input here) of the second amplifier 162, wherein the second feedback input terminal FB is further coupled to the output of the power supply to provide a second Group feedback input. The second amplifier output terminal VA is coupled to the output of the second amplifier 162 via the transistor 163 for the second set of feedback control. Wherein, the other input (here, the negative input) of the second amplifier 162 is coupled to the first reference voltage V _R1 .

FIG. 4 illustrates a voltage regulation circuit formed by using the controllable unit 128 according to an embodiment of the present invention. Please refer to FIG. 4 , for example, the voltage regulator circuit can be used as the voltage regulator 100 in FIG. 1 , which includes a transistor 110 , resistors 121 - 125 , and a capacitor 126 . In the voltage regulator 100 , the drain and the source of the transistor 110 respectively receive the voltage E ₁ and generate the output voltage V ₃ . The gate of the transistor 110 is coupled to the voltage E ₂ through the resistor 123 . The second amplifier output terminal VA is coupled to the gate of the transistor 110 and one terminal of the capacitor 126 . The other end of the capacitor 126 is coupled to the second feedback input end FB through the resistor 125 . The resistors 121 and 122 are connected in series between the output voltage V ₃ and the ground, and the second feedback input terminal FB is coupled between the resistors 121 and 122 .

FIG. 5 is a preferred embodiment of the oscillation circuit 200, wherein the resistor 205 is connected to a voltage-to-current converter through the oscillation frequency setting terminal RI. The voltage-to-current converter is composed of an amplifier 210 and a transistor 211 . The second reference level V _R2 is connected to the input of the amplifier 210 (the positive input here), and the second reference level V _R2 and the resistor 205 generate a frequency setting current. The transistors 212-217 form a current mirror circuit, and the current mirror circuit is used to generate the reference current I _R and the charging current and discharging current required by the oscillator. The oscillation control circuit is composed of comparators 230 , 235 , NAND gates 240 , 245 and an inverter 250 . The oscillation control circuit generates an oscillation signal PLS to control the switches 221 and 222 . The switches 221 and 222 respectively control the charging current and the discharging current of the capacitor 225 and generate a sawtooth signal V _SAW . The sawtooth signal V _SAW is between the clamp voltage V _H and V _L .

6 is a preferred embodiment of a protection unit 300, including an overvoltage protection circuit 310, an undervoltage protection circuit 350, an overcurrent protection circuit 320, an overpower protection circuit 330, an interface circuit 340, a power status indicating circuit and a power supply lockout circuit. The overvoltage protection circuit 310 and the low voltage protection circuit 350 are connected to the voltage input terminals V _n ˜V ₁ for detecting whether the output voltage of the power supply is too high or too low.

The power status indicating circuit is composed of an NOR gate 361, an NAND gate 375, a delay circuit 365 and a transistor 380, and is used to output a power status signal V _PG to the power status indicating terminal PG, and the power status signal indicates the status of the power supply. output status. When the output of the power supply is normal, that is, when neither the overvoltage protection circuit 310 nor the low voltage protection circuit 350 detects the output of overvoltage or low voltage, after the delay time of the delay circuit 365 is confirmed, the power supply status indication will be issued. The terminal PG outputs a power status signal V _PG .

The over-current protection circuit 320 is connected to the current detection terminals e _n -e ₁ , and cooperates with the voltage input terminals V _n -V ₁ to detect the over-current state of the output current of the power supply. The over-power protection circuit 330 is connected to the power detection terminal OPP for detecting the output power of the power supply. The interface circuit 340 includes a signal detection circuit and a power switch circuit. The signal detection circuit is coupled to the transformer 10 through the signal detection terminal UVAC for detecting the voltage level of the signal of the transformer 10 . The power switch circuit receives a power switch signal through the power switch input terminal PSON to determine whether the power supply is turned on or off. In addition, the interface circuit 340 cooperates with the outputs of the voltage protection circuits 310 and 350, the output of the signal detection circuit, and the power switch signal to output the power status signal V _PG through the power status indicating terminal PG to indicate the output status of the power supply. When the signal detection circuit of the interface circuit 340 detects via the signal detection terminal UVAC that the voltage level of the signal of the transformer 10 is lower than a sixth reference level V _R6 , it turns off its power status signal V _PG after a delay of a period of time. .

As for the power supply blocking circuit, it is composed of an OR gate 362, an inverting AND gate 376, a delay circuit 366, an inverter 371, and a D-type flip-flop 370 to generate a shutdown signal OFF. The power switch input terminal PSON receives the power switch signal and is used to control the shutdown signal OFF. When the power switch signal is turned on, the first output signal S ₁ and the second output signal S ₂ will be output through the turn off signal OFF. At this time, if any malfunction occurs in the power supply, the corresponding protection circuit will be activated, and the lock-off signal OFF will be turned off to cut off the first output signal S ₁ and the second output signal S ₂ . When the power switch signal is turned off, the power status signal V _PG of the power status indicator terminal PG will be turned off first, and after the delay time of the delay circuit 366, the D-type flip-flop 370 will be reset and the first output will be cut off by turning off the signal OFF. The signal S ₁ and the second output signal S ₂ . When the power switch signal resets the D-type flip-flop 370 , it will also reset the power blocking circuit at the same time, thereby releasing the locked state caused by the protection circuit.

7 is a preferred embodiment of a soft start circuit 400 according to the present invention, which includes an amplifier 430, a transistor 435 and a constant current source 410 to form a clamping amplifier circuit for generating a reference voltage V _REF . The startup capacitor 450 is connected to the constant current source 410 through the soft-start input SS. When the OFF signal OFF controls the switch 462 to turn on, the startup capacitor 450 is thus short-circuited, and thus the reference voltage V _REF will also be equal to zero voltage. When the signal OFF controls the switch 462 to be disconnected, the startup capacitor 450 will be charged by the constant current source 410 , and the reference voltage V _REF will gradually increase with the voltage on the startup capacitor 450 . And finally clamped at a level of the reference voltage V _R0 to generate a fixed reference voltage V _REF , and sent to the first amplifier 160 for the first set of feedback control.

The above-mentioned soft-start circuit soft-starts the reference voltage V _REF through the feedback loop, and its start-up speed is slow and not controlled by each phase (cycle-by-cycle), so it is especially suitable for proportional drive power supply Self-excited positive feedback drive circuit. In addition, the over-power protection signal OPH output by the power protection circuit 330 is further coupled to the soft-start capacitor 450 through the switch 461 . When the output power of the power supply exceeds a fourth reference level V _R4 , the constant current source 420 discharges the soft-start capacitor 450 to limit the maximum output power of the power supply. In this way, the output short circuit of the ratio-driven power supply can be adequately protected. So once the output of the power supply is shorted, it will restart its soft start to limit the power output.

8 and 9 are preferred embodiments of the overvoltage protection circuit 310 and the low voltage protection circuit 350 . The overvoltage protection circuit 310 and the low voltage protection circuit 350 respectively include a first set of clamping voltages and a second set of clamping voltages, and the "overvoltage" state means that the output voltage of the power supply exceeds the first set of clamping voltages. In addition, the "low voltage" status means that the output voltage of the power supply is lower than the second set of clamping voltages. The first group of clamping voltages is achieved by the third reference level V _R3 and resistors 515-519, and cooperates with comparators 512-514 and OR gate 511 to perform over-voltage protection, while the second group of clamping voltages is achieved by the third reference voltage It is achieved by leveling V _R3 and resistors 525-529, and cooperates with comparators 522-524 and OR gate 521 to perform low-voltage protection. When an "overvoltage" or "low voltage" condition occurs, the protection circuits (310 and 350) will respectively output an overvoltage protection signal OVP and an undervoltage protection signal UVP after a delay time to cut off the first output signal S ₁ and the second output signal S ₂ , and then turn off the power supply. The delay time is determined by the delay circuits 510 and 520 respectively.

FIG. 10 is a preferred embodiment of the overcurrent protection circuit 320 , which includes comparators 532 - 534 , constant current sources 538 - 539 , resistors 535 - 537 , an OR gate 531 and a delay circuit 530 . The constant current sources 538-539 and the resistors 535-537 each generate a clamping level between the voltages E _n ~ E ₁ (such as the voltages E ₁ and E ₂ in Figure 1) and the current detection terminals e _n ~ e ₁ . The output current of the power supply creates a voltage drop between the voltages E _n ˜ E ₁ and the voltage input terminals V _n ˜ V ₁ respectively through the impedances 96 , 92 , 93 . When the voltage drop is greater than the clamping level, the comparator will cut off the first output signal S ₁ and the second output signal S ₂ after the delay time of the OR gate 531 and the delay circuit 530 , and then turn off the power supply. Therefore, by changing the resistance values of the resistors 535-537, the current clamping level of the "over-current protection" output of each group can be changed.

FIG. 11 is a preferred embodiment of the overpower protection circuit 330 . It includes comparators 562 and 563 , each of which has a fourth reference level V _R4 and a fifth reference level V _R5 . When the output power of the power supply exceeds the fifth reference level V _R5 , the overpower protection circuit 330 will cut off the first output signal S ₁ and the second output signal S ₂ after a delay time, and then turn off the power supply. The delay time is determined by the delay circuit 560 . When the output power of the power supply exceeds the fourth reference level V _R4 , the overpower protection circuit 330 will immediately cut off the first output signal S ₁ and the second output signal S ₂ , and then immediately shut down the power supply.

FIG. 12 shows the interface circuit 340 , which includes a power switch circuit and a signal detection circuit, wherein the power switch circuit includes a comparator 571 , a debounce circuit 575 , a gate 585 and an inverter 583 . The comparator 571 has a seventh reference level V _R7 . When the voltage level of the power switch signal is higher or lower than the seventh reference level V _R7 , the power switch circuit will turn ON the signal generated by the AND gate 585 after a period of time (determined by the bounce circuit 575 ) for confirmation. to control the first output signal S ₁ and the second output signal S ₂ , and then turn on or turn off the power supply. The signal detection circuit includes a comparator 572 , a bounce circuit 576 , an NOR gate 587 , inverters 584 , 586 , a flip-flop 578 and a delay circuit 581 . When the signal of the transformer 10 is lower than the sixth reference level V _R6 , it will be confirmed after a period of time (determined by the bounce circuit 576 ), and then reset its power state signal V through the signal AOF generated by the inverting OR gate 587 _PG . In addition, through the inverter 586 , the power switch circuit of the power switch circuit will reset the power status signal V _PG by the signal AOF before turning off the first output signal S ₁ and the second output signal S ₂ . In addition, when the protection circuits 310, 350, the over-current protection circuit 320 and the over-power protection circuit 330 are shutting down the power supply, if the voltage level of the signal of the transformer 10 is higher than the sixth reference level V _R6 , the power supply The device will be turned off and latched. However, before the protection circuits 310, 350, over-current protection circuit 320, and over-power protection circuit 330 shut down the power supply, if the voltage level of the signal of the transformer 10 is already lower than the sixth reference level V _R6 , the power supply After the power supply is turned off, and after a delay time (determined by the delay circuit 581), the power supply will be restarted. This function will prevent the power supply from being shut down and locked due to the malfunction of the protection circuit during the process of shutting down the power supply.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes, but all the content that does not depart from the technical solution of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence still belong to the scope of the technical solution of the present invention.

Claims (28)

1. A control device for a proportional drive power supply, characterized in that it includes: A first feedback input terminal coupled to the output of the proportional drive power supply for providing a first set of feedback control for the proportional drive power supply; a first amplifier output terminal for providing feedback compensation; A soft-start input terminal is connected to a soft-start capacitor to set the soft-start time of the ratio-driven power supply; an oscillation frequency setting terminal connected to a resistor; At least one voltage input terminal coupled to the ratio-driven power supply; at least one current detection terminal coupled to the ratio-driven power supply; a power detection terminal, coupled to the ratio-driven power supply; a signal detection terminal coupled to a transformer of the ratio-driven power supply; a power switch input terminal; A power supply status indicator terminal; A first output terminal, used to output a first output signal, to couple and drive a first switching switch of the ratio-driven power supply; A second output terminal, used to output a second output signal, to couple and drive a second switching switch of the ratio-driven power supply, wherein the first switching switch is connected to the second switching switch and switches the the transformer of the ratio-driven power supply, and then control the output of the ratio-driven power supply; a first amplifier, the first input of which is connected to the first feedback input, the second input of the first amplifier is coupled to the soft-start input, the output of the first amplifier is coupled to the first amplifier output, Wherein the soft-start input terminal provides a reference voltage for the first amplifier; An oscillator connected to the oscillation frequency setting terminal for setting the oscillation frequency according to the resistance; A protection unit is used to connect to the voltage input terminal to detect the output voltage of the proportional driving power supply, and to connect to the current detection terminal to cooperate with the voltage input terminal to detect the proportional driving power supply The output current of the output current, connected to the power detection terminal to detect the output power of the proportional driving power supply, connected to the signal detection terminal to detect the voltage level of the secondary winding signal of the transformer, and connected to the power switch input terminal to receive a power switch signal; and an output circuit, electrically connected to the first amplifier, the oscillator, the protection unit, the first output terminal and the second output terminal, for generating and providing the first output according to the output of the first amplifier signal and the second output signal to the first output terminal and the second output terminal, the switching frequency of the first output signal and the second output signal is determined according to the output of the oscillator, and according to the output of the protection unit and decide to turn on and off the ratio-driven power supply; wherein the control device outputs a power supply status signal through the power supply status indication terminal according to the voltage input terminal, the signal detection terminal and the power switch input terminal to indicate The output status of the ratio-driven power supply. 2. The control device according to claim 1, further comprising: A second feedback input terminal, coupled to the output of the proportional driving power supply, for providing a second set of feedback control of the proportional driving power supply; a second amplifier, the first input of which is connected to the second feedback input, the second input of the second amplifier is connected to a first reference level; and A second amplifier output terminal, coupled to the output of the second amplifier, is used for the second group of feedback control. 3. The control device according to claim 1, wherein said protection unit comprises: A voltage protection circuit, connected to the voltage input terminal, is used to detect the overvoltage state and low voltage state of the output voltage of the proportional driving power supply; An overcurrent protection circuit, connected to the current detection terminal, used to cooperate with the voltage input terminal to detect the overcurrent state of the output current of the proportional drive power supply; An over-power protection circuit connected to the power detection terminal for detecting the output power of the ratio-driven power supply; a signal detection circuit, connected to the signal detection terminal, for detecting the voltage level of the secondary winding signal of the transformer; and A power switch circuit is connected to the power switch input end for receiving a power switch signal. 4. The control device according to claim 3, wherein the overvoltage state represents that one of the outputs of the proportional driving power supply exceeds a first clamping voltage, and the low voltage state represents that the proportional driving power supply One of the outputs of the type power supply is lower than a second clamping voltage, when the overvoltage or low voltage state occurs, the voltage protection circuit will cut off the first output signal and the second output after a delay of a first time signal, and then turn off the proportional driving power supply. 5. The control device according to claim 3, wherein the over-current status means that one of the output currents of the proportional driving power supply exceeds a first set of clamping levels, when an over-current status occurs , the overcurrent protection circuit cuts off the first output signal and the second output signal after a delay of a second time, and then turns off the proportional driving power supply. 6. The control device according to claim 3, wherein when the output power of the equal-ratio driving power supply exceeds a fifth reference level, the over-power protection circuit will be disabled after a delay of a third time the first output signal and the second output signal to turn off the proportional driving power supply; and When the output power of the proportional driving power supply exceeds a fourth reference level, the overpower protection circuit immediately cuts off the first output signal and the second output signal, and then immediately turns off the proportional driving power supply . 7. The control device according to claim 6, wherein the output of the over-power protection circuit is further coupled to the soft-start capacitor, so that when the output power of the proportional driving power supply exceeds the fourth When the reference level is reached, the over-power protection circuit will discharge the soft-start capacitor to limit the maximum output power of the proportional drive power supply. 8. The control device according to claim 3, wherein when the voltage level of the signal of the transformer is lower than a sixth reference level, the signal detection circuit will turn off the power supply after a delay of a fourth time status signal. 9. The control device according to claim 3, wherein When the voltage level of the power switch signal is higher or lower than a third reference level, the power switch circuit will control the first output signal and the second output signal after a fifth time of confirmation, and then turn on or off the proportional drive power supply; and The power switch circuit first turns off the power status signal before turning off the first output signal and the second output signal. 10. The control device according to claim 3, wherein When the voltage protection circuit, the over-current protection circuit and the over-power protection circuit shut down the proportional drive power supply, if the voltage level of the secondary winding signal of the transformer is higher than the sixth reference level, then the proportional drive power supply will be turned off; and Before the voltage protection circuit, the over-current protection circuit and the over-power protection circuit shut down the proportional drive power supply, if the voltage level of the secondary winding signal of the transformer is lower than the sixth reference level , the proportional driving power supply will be restarted after a sixth time delay after the proportional driving power supply is turned off. 11. A control device for proportional driving power supply, characterized in that it comprises: a first feedback input terminal connected to a first input of a first amplifier, wherein the first feedback input terminal is further coupled to the output of the proportional driving power supply, providing the proportional driving power supply The first group of feedback control; a first amplifier output coupled to the output of the first amplifier to provide feedback compensation; A soft-start input terminal is connected to a soft-start capacitor for setting the soft-start time of the equal-ratio driven power supply; the soft-start input terminal is further coupled to the second input of the first amplifier to provide the a first amplifier-reference voltage; a first output terminal and a second output terminal for outputting a first output signal and a second output signal; the first output signal and the second output signal operate according to the output of the first amplifier, and The first output signal is coupled to drive a first switch, and the second output signal is coupled to drive a second switch; wherein the first switch is connected to the second switch and switches the ratio-driven power supply a transformer for controlling the output of the ratio-driven power supply; At least one voltage input terminal is connected to a voltage protection circuit for detecting the over-voltage state and low-voltage state of the output voltage of the proportional driving power supply; a power detection terminal connected to an over-power protection circuit for detecting the output power of the ratio-driven power supply; a signal detection terminal coupled to the transformer and a signal detection circuit for detecting the voltage level of the signal of the transformer; a power switch input terminal, which receives a power switch signal and is connected to a power switch circuit, for turning on and off the ratio-driven power supply; and A power status indication terminal generates a power status signal according to the output of the voltage protection circuit, the output of the signal detection circuit and the power switch signal, and is used to indicate the output status of the proportional driving power supply. 12. The control device according to claim 11, further comprising: A second feedback input terminal is connected to the input of a second amplifier, wherein the second feedback input terminal is further coupled to the output of the proportional driving power supply to provide a first output of the proportional driving power supply. Two sets of feedback control; and A second amplifier output terminal is coupled to an output of the second amplifier for second group feedback control; wherein another input of the second amplifier is connected to a first reference level. 13. The control device according to claim 11, wherein said voltage protection circuit comprises a first set of clamping voltages and a second set of clamping voltages, and the overvoltage state means that the output of the power supply exceeds the The first set of clamping voltages; in addition, the low voltage state means that the output of the power supply is lower than the second set of clamping voltages; when an overvoltage state or a low voltage state occurs, the voltage protection circuit will delay for a first time , cut off the first output signal and the second output signal, and then turn off the proportional driving power supply. 14. The control device according to claim 11, wherein said over-power protection circuit includes a fifth reference level and a fourth reference level; Exceeding the fifth reference level, the over-power protection circuit will cut off the first output signal and the second output signal after a delay of a third time, and then turn off the proportional driving power supply; when the proportional When the output power of the driving power supply exceeds the fourth reference level, the overpower protection circuit will immediately cut off the first output signal and the second output signal, and then immediately shut down the proportional driving power supply. 15. The control device according to claim 14, wherein the output of the over-power protection circuit is further coupled to the soft-start capacitor, when the output power of the equal-ratio driven power supply exceeds the fourth reference level, the over-power protection circuit will discharge the soft-start capacitor to limit the maximum output power of the ratio-driven power supply. 16. The control device according to claim 11, wherein said signal detection circuit includes a sixth reference level; when the voltage level of the transformer signal is lower than the sixth reference level, the The signal detection circuit turns off the power status signal after a delay of a fourth time. 17. The control device according to claim 11, wherein said power switch circuit includes a seventh reference level; when the voltage level of the power switch signal is higher or lower than the seventh reference level , the power switch circuit will control the first output signal and the second output signal after a fifth time of confirmation, and then turn on or turn off the proportional driving power supply; wherein the power switch circuit is turning off the Before the first output signal and the second output signal, the power status signal will be turned off first. 18. The control device according to claim 11, wherein the voltage protection circuit and the overpower protection circuit, when the power supply is turned off, if the voltage level of the secondary winding signal of the transformer is higher than the first If the six reference levels are used, the equal-ratio driven power supply will be turned off; but before the voltage protection circuit and the over-power protection circuit turn off the power supply, if the voltage level of the transformer signal is lower than the sixth reference level, after the proportional driving power supply is turned off, after a sixth time delay, the proportional driving power supply will be restarted. 19. A control device for a power supply, characterized in that it comprises: a first feedback input terminal connected to a first input of a first amplifier, wherein the first feedback input terminal is further coupled to the output of the power supply to provide a first set of feedback control of the power supply; a first amplifier output coupled to the output of the first amplifier to provide feedback compensation; a soft-start input terminal connected to a soft-start capacitor for setting the soft-start time of the power supply; the soft-start input terminal is further coupled to the second input of the first amplifier to provide the first amplifier with a reference voltage; A first output terminal and a second output terminal are used to output a first output signal and a second output signal; the first output signal and the second output signal operate according to the output of the first amplifier, and Coupling and driving a first switch and a second switch; wherein the first switch is connected to the second switch and switches a transformer of the power supply, thereby controlling the output of the power supply; and A power switch input end receives a power switch signal and is connected to a power switch circuit for turning on and off the power supply. 20. The control device according to claim 19, wherein said power switch circuit includes a sixth reference level; when the voltage level of the power switch signal is higher or lower than the sixth reference level, The power switch circuit controls the first output signal and the second output signal to turn on or turn off the power supply after a fifth time is confirmed. 21. A control device for a power supply, characterized in that it comprises: At least one voltage input terminal is connected to a voltage protection circuit for detecting the overvoltage state and the low voltage state of the output voltage of the power supply; At least one current detection terminal is connected to an overcurrent protection circuit, and cooperates with the voltage input terminal to detect the overcurrent state of the output current of the power supply; a power detection terminal connected to an over-power protection circuit for detecting the output power of the power supply; a signal detection terminal coupled to a transformer of the power supply and a signal detection circuit to detect the voltage level of the signal of the transformer; a power switch input end, which receives a power switch signal and is connected to a power switch circuit for turning on and off the power supply; A power supply status indication terminal, which generates a power supply status signal according to the output of the voltage protection circuit, the output of the signal detection circuit and the power switch signal, and is used to indicate the output status of the power supply; and A power protection output terminal generates a power protection signal according to the voltage protection circuit, the over-current protection circuit and the over-power protection circuit for shutting down the power supply. 22. The control device according to claim 21, wherein the voltage protection circuit includes a first set of clamping voltages and a second set of clamping voltages, and the over-voltage state means that the output of the power supply exceeds the first group clamping voltage; in addition, the low voltage state means that the output of the power supply is lower than the second group clamping voltage; when the overvoltage state or low voltage state occurs, the voltage protection circuit will generate the power protection signal, and then shut down the power supply. 23. The control device according to claim 21, wherein said over-current protection circuit comprises a first set of clamping levels, and the over-current status means that the output current of the power supply exceeds the first set of clamping levels. Clamping level: when the over-current state occurs, the over-current protection circuit will generate the power protection signal after a delay of a second time, and then shut down the power supply. 24. The control device according to claim 21, wherein said over-power protection circuit includes a fifth reference level and a fourth reference level; when the output power of the power supply exceeds the fifth reference level, the over-power protection circuit will generate a power protection signal after a delay of a third time, and then shut down the power supply; when the output power of the power supply exceeds the fourth reference level, the over-power protection The circuit will immediately generate the power protection signal, and then shut down the power supply immediately. 25. The control device according to claim 24, wherein the output of the over-power protection circuit is further coupled to the soft-start capacitor, when the output power of the power supply exceeds the fourth reference level, the The over-power protection circuit will discharge the soft-start capacitor to limit the maximum output power of the power supply. 26. The control device according to claim 21, wherein said signal detection circuit includes a sixth reference level; when the voltage level of the secondary winding signal of the transformer is lower than the sixth reference level Normally, the signal detection circuit will turn off the power status signal after a delay of a fourth time. 27. The control device according to claim 21, wherein said power switch circuit includes a seventh reference level; when the voltage level of the power switch signal is higher or lower than the seventh reference level , the power switch circuit will generate the power protection signal after a fifth time of confirmation, and then turn on or off the power supply; wherein the power switch circuit will first turn off the power supply before generating the power protection signal Signal. 28. The control device according to claim 21, characterized in that when the voltage protection circuit, the over-current protection circuit and the over-power protection circuit shut down the power supply, if the voltage of the secondary winding signal of the transformer exceeds level is higher than the sixth reference level, the power supply will be turned off; but when the voltage protection circuit, the overcurrent protection circuit and the overpower protection circuit, before turning off the power supply, if the signal of the transformer If the voltage level is lower than the sixth reference level, after the power supply is turned off, the power supply will be restarted after a sixth time delay.

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