Wide-voltage low-power-consumption starting circuit and switching power supply

Abstract

The utility model discloses a wide-voltage low-power-consumption starting circuit and a switching power supply, and belongs to the technical field of wide-voltage starting circuits, the wide-voltage low-power-consumption starting circuit specifically comprises a starting resistor, a switching circuit, an isolation circuit, a power supply circuit, a driving circuit and a conversion circuit, the starting resistor is connected with a high-voltage bus (HV), and is used for reducing voltage and providing starting voltage for the driving circuit at the starting moment; the switching circuit is connected with a high-voltage bus (HV) and is used for providing forward / reverse bias voltage and controlling the on / off of the NMOS transistor Q1; the power supply circuit is connected with the isolation circuit and the driving circuit, is coupled with the conversion circuit and is used for providing working voltage for the driving circuit to realize closed-loop power supply; the circuit is simple in structure and low in manufacturing cost. The switching power supply with a wide input voltage range can be quickly started, after the switching power supply is normally started, the starting resistor circuit is directly turned off, the power consumption of the switching power supply is reduced, and the conversion efficiency of the switching power supply is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of wide voltage starting circuits, in particular to a wide voltage low power consumption starting circuit and a switching power supply. Background Art

[0002] There are differences in electricity standards in different countries around the world. For example, the standard for residential electricity is 60Hz 120V in the United States, 50Hz 220V in China, and 50Hz 230V in the United Kingdom, Germany, and France. When traveling on business or abroad, you often encounter the problem of mismatched power converters.

[0003] Some switching power supply manufacturers have proposed to manufacture electronic products suitable for wide voltage environments by voltage segmentation, such as 100~277V and 200~264V.

[0004] The production of electronic products suitable for a wide voltage range of 100 to 380 V requires solving the following technical problems:

[0005] 1. Low voltage input, the startup time is too long or it is difficult to start at low voltage;

[0006] 2. High voltage input, high startup power consumption, or burning out the driver chip.

[0007] The solution is to design a step-down circuit between the high voltage and the driving voltage to reduce the impact of the high voltage on the driving chip and select a resistor for voltage reduction. When the resistance of the resistor is too large, the voltage division is too large, and there will be problems such as long startup time or difficulty in starting in a low-voltage environment; when the resistance of the resistor is too small, it cannot play a role in reducing the voltage. Utility Model Content

[0008] The main purpose of the utility model is to solve the above-mentioned technical problems.

[0009] According to the utility model, a wide voltage and low power consumption starting circuit is proposed, the starting circuit comprises: a starting resistor, a switch circuit, a power supply circuit, a drive circuit and a conversion circuit;

[0010] The startup resistor includes a resistor R1, a front end of the resistor R1 is connected to a high voltage bus HV port, a rear end of the resistor R1 is connected to a drain of an NMOS transistor Q1, and a source of the NMOS transistor Q1 is connected to a VCC port of the drive circuit;

[0011] The switch circuit includes a resistor R2, a voltage stabilizing diode ZD1 and an NMOS transistor Q1, wherein the front end of the resistor R2 is connected to the high voltage bus HV port, the rear end of the resistor R2 is connected to the gate of the NMOS transistor Q1, the cathode of the voltage stabilizing diode ZD1 is connected to the gate of the NMOS transistor Q1, and the anode of the voltage stabilizing diode ZD1 is grounded;

[0012] The power supply circuit includes a capacitor C2, a transistor Q2, a voltage stabilizing diode ZD2, a diode D2, a resistor R7, a resistor R8 and an auxiliary winding T1B, the emitter of the transistor Q2 is connected to the VCC port of the drive circuit, the collector of the transistor Q2 is connected to the cathode of the diode D2, the anode of the diode D2 is connected to the front end of the resistor R8, the rear end of the resistor R8 is connected to the same-name end of the auxiliary winding T1B, the opposite-name end of the auxiliary winding T1B is grounded, one end of the resistor R7 is connected to the collector of the transistor Q2, the other end of the resistor R7 is connected to the base of the transistor Q2, the upper plate of the capacitor C2 is connected to the emitter of the transistor Q2, and the lower plate of the capacitor C2 is grounded;

[0013] The drive circuit includes a drive chip U1, and the conversion circuit includes an NMOS transistor Q3, a resistor R6 and a primary winding T1A. The gate of the NMOS transistor Q3 is connected to the output port DR of the drive circuit through the resistor R6, the drain of the NMOS transistor Q3 is connected to the opposite-name end of the primary winding T1A, and the same-name end of the primary winding T1A is connected to the high-voltage bus HV port; the primary winding T1A is coupled to the auxiliary winding T1B.

[0014] Preferably, the startup circuit also includes an isolation circuit, which includes a diode D1 and a capacitor C1, the cathode of the diode D1 is connected to the upper plate of the capacitor C1, the anode of the diode D1 is connected to the emitter of the transistor Q2 in the power supply circuit, the lower plate of the capacitor C1 is grounded, and the common end of the diode D1 and the capacitor C1 is connected to the VCC port of the drive circuit.

[0015] Preferably, the resistor R1 includes a plurality of resistors connected in series.

[0016] Preferably, the resistor R2 includes a plurality of resistors connected in series.

[0017] A switching power supply comprises the above wide voltage and low power consumption starting circuit.

[0018] The technical solution of the utility model adopts a starting resistor. When the switching power supply is turned on, the NMOS transistor Q1 is turned on, and the high-voltage bus (HV) provides a starting voltage to the driver chip U1 of the driving circuit through the resistor R1 and the NMOS transistor Q1. At the same time, the NMOS transistor Q1, the voltage stabilizing diode ZD1, and the resistor R2 in the switching circuit form a voltage stabilizing circuit. The voltage stabilizing diode ZD1 is a certain voltage stabilizing value, so that the source voltage of the NMOS transistor Q1 meets the minimum starting voltage of the driver chip U1 in the driving circuit 5, and the driver chip U1 can be quickly started. The circuit structure is simple and the manufacturing cost is low. It can realize fast startup for a switching power supply with a wide input voltage range. After the switching power supply is normally started, the starting resistor circuit is directly turned off to reduce the power consumption of the switching power supply and improve the conversion efficiency of the switching power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] With reference to the accompanying drawings, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings are only used for illustrative purposes and are not intended to limit the protection scope of the present utility model.

[0020] Figure 1 This is a schematic diagram of a wide voltage and low power consumption startup circuit according to an embodiment of the utility model.

[0021] Description of Figure Numbers:

[0022] 100. Starting circuit; 1. Starting resistor; 2. Switching circuit; 3. Isolation circuit; 4. Power supply circuit; 5. Driving circuit; 6. Conversion circuit. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0024] The utility model provides a wide voltage and low power consumption starting circuit, and the starting circuit 100 comprises:

[0025] A starting resistor 1, connected to the high voltage bus (HV), is used to reduce the voltage at the start moment and provide a starting voltage to the drive circuit 5;

[0026] The switch circuit 2 is connected to the high voltage bus (HV) and is used to provide a forward / reverse bias voltage to control the NMOS transistor Q1 to be turned on / off;

[0027] The isolation circuit 3 is connected to the power supply circuit 4, and isolates the capacitor in the power supply circuit 4 at the moment of startup to reduce the starting voltage;

[0028] The power supply circuit 4 is connected to the isolation circuit 3 and the drive circuit 5, and coupled to the conversion circuit 6, and is used to provide a working voltage to the drive circuit 5 to realize a closed-loop power supply;

[0029] The driving circuit 5 is connected to the conversion circuit 6 and is used to drive the subsequent conversion circuit 6 to work;

[0030] The conversion circuit 6 is connected to the high voltage bus (HV), coupled to the power supply circuit 4 and provides a supply voltage thereto.

[0031] Figure 1 The schematic diagram of the wide voltage and low power consumption startup circuit involved in the embodiment of the present application. The startup circuit 100 includes a startup resistor 1, a switch circuit 2, an isolation circuit 3, a power supply circuit 4, a drive circuit 5 and a conversion circuit 6. The HV port is the power supply end of the high-voltage bus, the VCC port is the power supply voltage of the drive circuit, and the DR port is the output end of the drive circuit. The startup resistor 1 can reduce the high voltage (HV) of the high-voltage bus to the power supply voltage (VCC) range of the drive circuit 5 and drive the driver chip U1 in the circuit to start working. After the driver chip U1 is started, the drive post-stage conversion circuit 6 is coupled with the power supply circuit 4, and the power supply circuit 4 provides a working voltage to the driver chip U1 of the drive circuit 5. When the power supply voltage of the power supply circuit 4 is greater than the total voltage on the startup resistor 1, the NMOS transistor Q1 and the voltage regulator diode ZD1, the NMOS transistor Q1 is turned off to realize the closed-loop power supply to the driver chip U1.

[0032] The startup resistor 1 can be formed by multiple resistors connected in series, or it can be composed of a single resistor. When multiple resistors are connected in series, multi-stage voltage reduction is achieved. In the embodiment, a single resistor R1 is used as an example for explanation. The front end of the resistor R1 is connected to the high-voltage bus HV port, the rear end of the resistor R1 is connected to the drain of the NMOS transistor Q1, and the source of the NMOS transistor Q1 is connected to the VCC port of the drive circuit 5. The high-voltage bus HV port provides a startup voltage to the drive chip U1 through the NMOS transistor Q1.

[0033] The switch circuit 2 includes a resistor R2, a voltage-stabilizing diode ZD1, and an NMOS transistor Q1. The front end of the resistor R2 is connected to the high-voltage bus HV port, the rear end of the resistor R2 is connected to the gate of the NMOS transistor Q1, the cathode of the voltage-stabilizing diode ZD1 is connected to the gate of the NMOS transistor, and the anode of the voltage-stabilizing diode ZD1 is grounded. The resistor R2 can be formed by multiple resistors connected in series, or it can be composed of a single resistor. When multiple resistors are connected in series, multi-stage voltage reduction is achieved. In the embodiment, a single resistor R2 is used as an example for explanation.

[0034] When the switch circuit 2 is connected to the high-voltage bus (HV), the resistor R2 and the voltage-stabilizing diode ZD1 provide a forward bias voltage to the gate of the NMOS transistor Q1, the NMOS transistor Q1 is turned on, and the high-voltage bus (HV) starts to supply power to the driver chip U1 through the resistor R1 and the NMOS transistor Q1. At the same time, the switch circuit 2 also has a linear voltage stabilization function.

[0035] The isolation circuit 3 includes a diode D1 and a capacitor C1. The cathode of the diode D1 is connected to the upper plate of the capacitor C1, the anode of the diode D1 is connected to the power supply circuit 4, the lower plate of the capacitor C1 is grounded, and the common end of the diode D1 and the capacitor C1 is connected to the VCC port of the drive circuit 5.

[0036] The isolation circuit 3 can isolate the capacitor on the power supply circuit 4 from causing the startup voltage to be lowered at the moment of startup, thereby realizing a fast startup of the driver chip U1.

[0037] The power supply circuit 4 includes a capacitor C2, a transistor Q2, a voltage-stabilizing diode ZD2, a diode D2, a resistor R7, a resistor R8 and an auxiliary winding T1B. The emitter of the transistor Q2 is connected to the positive electrode of the diode D1, the collector of the transistor Q2 is connected to the negative electrode of the diode D2, the positive electrode of the diode D2 is connected to the front end of the resistor R8, the rear end of the resistor R8 is connected to the same-name end of the auxiliary winding T1B, the auxiliary winding T1B is coupled with the primary winding T1A in the conversion circuit 6, the base of the transistor Q2 is connected to the negative electrode of the voltage-stabilizing diode ZD2, the positive electrode of the voltage-stabilizing diode ZD2 is grounded, the opposite-name end of the auxiliary winding T1B is grounded, one end of the resistor R7 is connected to the collector of the transistor Q2, and the other end is connected to the base of the transistor Q2, the upper plate of the capacitor C2 is connected to the emitter of the transistor Q2, and the lower plate of the capacitor C2 is grounded.

[0038] The power supply circuit 4 supplies power to the driving circuit 5. The voltage stabilizing circuit is composed of the voltage stabilizing diode ZD2, the transistor Q2 and the resistor R7. The capacitor C2 can filter out clutter.

[0039] The driving circuit 5 includes a driving chip U1 , which is connected to a VCC port of the driving circuit 5 , and an output port DR drives a subsequent conversion circuit 6 .

[0040] The conversion circuit 6 includes an NMOS transistor Q3, a resistor R6 and a primary winding T1A. The collector of the NMOS transistor Q3 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the output end DR port of the drive circuit 5, the drain of the NMOS transistor Q3 is connected to the opposite end of the primary winding T1A, and the same end of the primary winding T1A is connected to the high-voltage bus HV port. The conversion circuit 6 outputs energy to the auxiliary winding T1B under the previous stage drive signal.

[0041] Working principle of wide voltage and low power consumption startup circuit:

[0042] At the moment the switching power supply is turned on, the NMOS transistor Q1 is turned on, and the high-voltage bus (HV) provides a starting voltage to the driver chip U1 of the driving circuit 5 through the resistor R1 and the NMOS transistor Q1. At the same time, the NMOS transistor Q1, the voltage-stabilizing diode ZD1, and the resistor R2 in the switching circuit 2 form a voltage-stabilizing circuit. The voltage-stabilizing diode ZD1 is a certain voltage-stabilizing value, so that the source voltage of the NMOS transistor Q1 meets the minimum starting voltage of the driver chip U1 in the driving circuit 5, and the driver chip U1 can be quickly started.

[0043] The driving chip U1 is started, and the output port DR of the driving circuit 5 drives the conversion circuit 6 to work. The primary winding T1A is coupled with the auxiliary winding T1B, and drives the power supply circuit 4 to work. The diode D2 rectifies, and the working voltage is output from the emitter of the transistor Q2. After being rectified by the diode D1, the working voltage is provided to the driving circuit 5 to realize closed-loop power supply.

[0044] The driving chip U1 of the driving circuit 5 works normally, and the isolation circuit 3 applies the power supply voltage to the source of the NMOS transistor Q1. The voltage stabilization value of the voltage stabilization diode ZD2 is set to be greater than the voltage stabilization value of the voltage stabilization diode ZD1, preferably greater than 3 to 8V, and more preferably greater than 2 to 5V. At this time, the total voltage value on the resistor R1, the NMOS transistor Q1 and the voltage stabilization diode ZD1 is lower than the voltage value of the output end of the power supply circuit 4 after passing through the diode D1. At this time, the NMOS transistor Q1 is turned off, and the driving chip U1 of the driving circuit 5 is powered by the power supply circuit 4 and works normally.

[0045] The startup circuit 100 can realize fast startup of a wide-voltage switching power supply and reduce power consumption.

[0046] The startup circuit 100 in the above embodiment is applied to a switching power supply, and can realize fast startup for a switching power supply with a wide input voltage range. After the switching power supply starts normally, the startup resistance circuit is directly turned off, thereby reducing the power consumption of the switching power supply and improving the conversion efficiency of the switching power supply.

[0047] It should be noted that the starting resistor 1 can be selected with a lower resistance value, so that when the low voltage input is met, the driver chip U1 can be powered quickly and started to work; the starting resistor 1 can be selected with a resistor with high power consumption, and it can even be overloaded and used at full power for a short period of time. After the switching power supply is started, the NMOS transistor Q1 is cut off to ensure the safety of the circuit and reduce the power consumption of the starting circuit 100.

Claims

1. Wide voltage and low power consumption startup circuit, characterized in that: The starting circuit (100) comprises: a starting resistor (1), a switch circuit (2), a power supply circuit (4), a drive circuit (5) and a conversion circuit (6); The starting resistor (1) comprises a resistor R1, the front end of the resistor R1 is connected to the high voltage bus HV port, the rear end of the resistor R1 is connected to the drain of the NMOS transistor Q1, and the source of the NMOS transistor Q1 is connected to the VCC port of the drive circuit (5); The switch circuit (2) comprises a resistor R2, a voltage stabilizing diode ZD1 and an NMOS transistor Q1, wherein the front end of the resistor R2 is connected to the high voltage bus HV port, the rear end of the resistor R2 is connected to the gate of the NMOS transistor Q1, the cathode of the voltage stabilizing diode ZD1 is connected to the gate of the NMOS transistor Q1, and the anode of the voltage stabilizing diode ZD1 is grounded; The power supply circuit (4) comprises a capacitor C2, a transistor Q2, a voltage stabilizing diode ZD2, a diode D2, a resistor R7, a resistor R8 and an auxiliary winding T1B, the emitter of the transistor Q2 is connected to the VCC port of the drive circuit (5), the collector of the transistor Q2 is connected to the cathode of the diode D2, the anode of the diode D2 is connected to the front end of the resistor R8, the rear end of the resistor R8 is connected to the same-name end of the auxiliary winding T1B, the opposite-name end of the auxiliary winding T1B is grounded, one end of the resistor R7 is connected to the collector of the transistor Q2, the other end of the resistor R7 is connected to the base of the transistor Q2, the upper plate of the capacitor C2 is connected to the emitter of the transistor Q2, and the lower plate of the capacitor C2 is grounded; The drive circuit (5) comprises a drive chip U1, and the conversion circuit (6) comprises an NMOS transistor Q3, a resistor R6 and a primary winding T1A, the gate of the NMOS transistor Q3 is connected to the output end DR port of the drive circuit (5) through the resistor R6, the drain of the NMOS transistor Q3 is connected to the opposite end of the primary winding T1A, and the same end of the primary winding T1A is connected to the high-voltage bus HV port; the primary winding T1A is coupled to the auxiliary winding T1B.

2. The wide voltage and low power consumption starting circuit according to claim 1, characterized in that: The start-up circuit (100) further comprises an isolation circuit (3), the isolation circuit (3) comprising a diode D1 and a capacitor C1, the cathode of the diode D1 being connected to the upper plate of the capacitor C1, the anode of the diode D1 being connected to the emitter of the transistor Q2 in the power supply circuit (4), the lower plate of the capacitor C1 being grounded, and the common end of the diode D1 and the capacitor C1 being connected to the VCC port of the drive circuit (5).

3. The wide voltage and low power consumption starting circuit according to claim 2, characterized in that: The resistor R1 includes a plurality of resistors connected in series.

4. The wide voltage and low power consumption starting circuit according to claim 2, characterized in that: The resistor R2 includes a plurality of resistors connected in series.

5. A switching power supply, characterized in that: The invention comprises the wide voltage and low power consumption starting circuit as described in any one of claims 1 to 2.

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