A switching power supply enabling control circuit

Abstract

The utility model discloses a switch power supply enable control circuit, including positive and negative logic enable control circuit and positive and negative logic level regulation circuit, positive and negative logic enable control circuit positive and negative logic enable control circuit including resistance R1, resistance R2, electric capacity C1, diode D1, diode D2, MOS tube Q1 and stabilivolt Z1, positive and negative logic level regulation circuit including resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, electric capacity C2, electric capacity C3, electric capacity C4 and chip IC1. The switch power supply enable control circuit provided by the utility model can select corresponding positive and negative logic control through selecting corresponding circuit when using, and can adjust high and low level range at the same time, greatly improves the versatility of scheme. The utility model can be used for different model PWM control chip when using, and has the advantages of strong versatility, small size, low cost, safe and stable, and wide application prospect.

Description

Technical Field

[0001] This utility model belongs to the field of switching power supply circuit design technology, specifically relating to a switching power supply enable control circuit. Background Technology

[0002] Currently, switching power supply modules are typically controlled to turn on and off by controlling the enable pin level. A positive logic level (high or floating) indicates the module is working, while a low level or ground indicates the module is not working; a negative logic level (high or floating) indicates the module is not working, while a low level or ground indicates the module is working.

[0003] For modules of the same specification, there is often a distinction between positive and negative logic during use, and the control level also has requirements. Due to this distinction, the underlying principles of the two control methods are crucial. When there are many components, and the circuit principles differ, complete compatibility between the positive and negative logic circuits may not be possible. Given a fixed size, separately fabricating PCBs for the positive and negative enable logic may affect the electrical characteristics of switching power supply modules of the same specification. Therefore, a simple and effective enable control circuit that is compatible with both positive and negative logic can significantly reduce costs and ensure that all electrical performance characteristics of the power supply module remain consistent except for logic control. Thus, the enable control circuit must be designed to be as simple as possible while still fulfilling its control function. Summary of the Invention

[0004] The purpose of this invention is to provide a switching power supply enable control circuit that addresses existing switching power supply enable control methods. This circuit can simultaneously incorporate both positive and negative logic control modes and allows adjustment of the high and low level ranges.

[0005] To achieve the above objectives, the technical solution adopted by this utility model includes: This utility model provides a switching power supply enable control circuit, including a positive and negative logic enable control circuit and a positive and negative logic level adjustment circuit; wherein: The positive and negative logic enable control circuit includes resistors R1 and R2, capacitor C1, diodes D1 and D2, MOSFET Q1, and Zener diode Z1. One end of capacitor C1, the cathodes of diodes D1 and D2 are connected to the EN terminal, and the other end of capacitor C1 is grounded. The anode of diode D1 and pin 3 of MOSFET Q1 are connected to ENA. The anode of diode D2, one end of resistor R1, one end of resistor R2, pin 1 of MOSFET Q1, and one end of Zener diode Z1 are all connected together. The other end of resistor R1 is connected to the +10V power supply terminal, and the other end of resistor R2, pin 2 of MOSFET Q1, and the other end of Z1 are grounded (PGND). The positive and negative logic level adjustment circuit (2) includes resistors R3, R4, R5, R6, R7, and R8, capacitors C2, C3, and C4, and chip IC1; wherein, one end of resistor R4 and one end of resistor R6 are connected to ENA; the other end of resistor R6, one end of resistor R7, one end of resistor R5, and one end of capacitor C3 are connected together; the other end of resistor R4 and one end of resistor R3 are connected together to the VIN+ power supply terminal; the other end of resistor R5 is connected to chip IC1. Pin 3 of IC1 and pin 10 of IC1 are left floating. Pins 4, 5, 7, and 1 of IC1 are irrelevant to the above description and will not be explained further here. One end of resistor C4 is connected to pin 9 (SS) of IC1. Pin 8 of IC1 is connected to one end of resistor R8. The other ends of resistor R7, capacitor C3, capacitor C4, resistor R8, and pin 6 of IC1 are all grounded (PGND). One end of capacitor C2 is grounded, and the other end of capacitor C2 and the other end of resistor R3 are connected to pin 2 of IC1.

[0006] This utility model also includes the following other technical features: The diodes D1 and D2 mentioned are both model 1N4148WT.

[0007] The MOSFET Q1 mentioned is model 2N7002T.

[0008] The Zener diode Z1 is model BZX584C5V1.

[0009] The resistors R1 and R2 have a resistance of 5.1KΩ, the capacitor C1 has a resistance of 0.1uF / 50V, the resistor R3 has a resistance of 200Ω, the resistor R4 has a resistance of 20KΩ, the resistor R5 has a resistance of 1KΩ, the resistor R6 has a resistance of 4.7KΩ, the resistor R7 has a resistance of 9.1KΩ, the resistor R8 has a resistance of 24KΩ, the capacitor C2 has a resistance of 0.47uF / 50V, the capacitor C3 has a resistance of 0.1uF / 50V, and the capacitor C4 has a resistance of 0.47uF / 50V.

[0010] The chip IC1 mentioned is model VPC2187B.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: The switching power supply enable control circuit provided by this invention allows for flexible selection of positive and negative logic control and voltage range adjustment, greatly improving the versatility of the PCB. This invention can be used with different PWM control chips, offering strong versatility, small size, low cost, safety, and stability, with broad application prospects. Attached Figure Description

[0012] Figure 1 The circuit diagram for the positive and negative logic enable control circuit; Figure 2 This is a circuit diagram for adjusting positive and negative logic levels. Detailed Implementation

[0013] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0014] The present invention will now be described in further detail with reference to the accompanying drawings: This utility model discloses a switching power supply enable control circuit, including a positive and negative logic enable control circuit and a positive and negative logic level adjustment circuit. The positive and negative logic enable control circuit is used to implement positive and negative logic enable control; the positive and negative logic level adjustment circuit is used to implement the function of adjusting the range of positive and negative logic enable control levels.

[0015] like Figure 1 , Figure 2 As shown, the positive and negative logic enable control circuit includes resistors R1 and R2, capacitor C1, diodes D1 and D2, MOSFET Q1, and Zener diode Z1. One end of capacitor C1, the cathodes of diodes D1 and D2 are all connected to the EN terminal, and the other end of capacitor C1 is grounded. The anode of diode D1 and pin 3 of MOSFET Q1 are connected to ENA. The anode of diode D2, one end of resistor R1, one end of resistor R2, pin 1 of MOSFET Q1, and one end of Zener diode Z1 are all connected together. The other end of resistor R1 is connected to the +10V power supply terminal, and the other end of resistor R2, pin 2 of MOSFET Q1, and the other end of Z1 are grounded (PGND). The positive and negative logic level adjustment circuit includes resistors R3, R4, R5, R6, R7, and R8, capacitors C2, C3, and C4, and chip IC1. One end of resistor R4 and one end of resistor R6 are connected to ENA; the other end of resistor R6, one end of resistor R7, one end of resistor R5, and one end of capacitor C3 are connected together; the other end of resistor R4 and one end of resistor R3 are connected to the VIN+ power supply terminal; and the other end of resistor R5 is connected to pin 3 of chip IC1. Pin 10 of IC1 is left floating. Pins 4, 5, 7, and 1 of IC1 are not related to the circuit of this utility model and need not be explained here. One end of resistor C4 is connected to pin 9 (SS) of chip IC1. Pin 8 of IC1 is connected to one end of resistor R8. The other ends of resistor R7, capacitor C3, capacitor C4, resistor R8, and pin 6 of chip IC1 are all grounded (PGND). One end of capacitor C2 is grounded, and the other end of capacitor C2 and the other end of resistor R3 are connected to pin 2 of chip IC1.

[0016] Preferably, diodes D1 and D2 are model 1N4148WT, MOSFET Q1 is model 2N7002T, Zener diode Z1 is model BZX584C5V1, and chip IC1 is model VPC2187B.

[0017] Preferably, taking an input voltage range of 9V-36V as an example, the resistance of resistor R1 is 5.1K, the resistance of resistor R2 is 5.1K, the parameter of capacitor C1 is 0.1uF / 50V, the resistance of resistor R3 is 200R, the resistance of resistor R4 is 20K, the resistance of resistor R5 is 1K, the resistance of resistor R6 is 4.7K, the resistance of resistor R7 is 9.1K, the resistance of resistor R8 is 24K, the parameter of capacitor C2 is 0.47uF / 50V, the parameter of capacitor C3 is 0.1uF / 50V, and the parameter of capacitor C4 is 0.47uF / 50V.

[0018] The working principle of this utility model is as follows: Positive logic enable control circuit: C1 and D1 are connected to the circuit. When the EN terminal is high or floating, the voltage at the ENA terminal is slightly higher than the voltage at pin 3 of chip IC1. At this time, since the forward voltage of D1 is less than the turn-on voltage of D1, D1 cannot be turned on. Therefore, the actual voltage at pin 3 of chip IC1 will be higher than the turn-on voltage. At this time, chip IC1 works normally, and the switching power supply works normally. When the EN terminal is low or grounded, the forward voltage of D1 is greater than the turn-on voltage of D1, and D1 is turned on. At this time, the ENA voltage is pulled low, and the actual voltage at pin 3 of chip IC1 will be lower than the turn-on voltage. Chip IC1 is turned off, and the switching power supply does not work.

[0019] Negative logic enable control circuit: Capacitor C1, diode D2, resistors R1 and R2, MOSFET Q1, and Zener diode Z1 are connected to the circuit. The +10V power supply is divided by R1 and R2 and regulated by Z1. The voltage at pin 1 of Q1 is 5V, the MOSFET is turned on, and the ENA voltage is pulled down to 0V. When the EN terminal is high or floating, the forward voltage of D2 is less than its turn-on voltage, so D2 cannot conduct. Therefore, the ENA voltage remains 0V, and the actual voltage at pin 3 of chip IC1 will be lower than the turn-on voltage, and the switching power supply does not work. When the EN terminal is low or grounded, the forward voltage of D2 is greater than its turn-on voltage, so D2 conducts. The voltage at pin 1 of Q1 is pulled low, Q1 cannot conduct, and ENA remains high. The actual voltage at pin 3 of chip IC1 will be higher than the turn-on voltage. At this time, chip IC1 works normally, and the switching power supply works normally.

[0020] Positive and negative logic level adjustment circuit: R3, R4, R5, R6, R7, R8, C2, C3, C4, IC1. Pin 3 of chip IC1 controls the on / off state of chip IC1 through current limiting by resistor R5 and voltage division by resistors R4, R6, and R7. After the undervoltage parameter is adjusted, while keeping the total value of resistors R4, R6, and R7 constant, the on / off level of the positive and negative logic can be changed by altering the ratio of the values ​​of resistors R4 and R6. When the ratio of the resistance value of R6 increases, the voltage point for enabling or disabling will increase, thereby changing the range of the enable control level.

[0021] The switching power supply enable control circuit provided by this utility model can be used with different PWM control chips, has strong versatility, small size, low cost, safety and stability, and has broad application prospects.

[0022] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be conceived by those skilled in the art within the technical scope disclosed in the present utility model without creative effort should be included within the protection scope of the present utility model.

Claims

1. A switching power supply enable control circuit, characterized in that, Includes positive and negative logic enable control circuits and positive and negative logic level adjustment circuits; wherein: The positive and negative logic enable control circuit includes resistors R1 and R2, capacitor C1, diodes D1 and D2, MOSFET Q1, and Zener diode Z1. One end of capacitor C1, the cathodes of diodes D1 and D2 are all connected to the EN terminal, and the other end of capacitor C1 is grounded. The anode of diode D1 and pin 3 of MOSFET Q1 are connected to ENA. The anode of diode D2, one end of resistor R1, one end of resistor R2, pin 1 of MOSFET Q1, and one end of Zener diode Z1 are all connected together. The other end of resistor R1 is connected to the +10V power supply terminal, and the other end of resistor R2, pin 2 of MOSFET Q1, and the other end of Z1 are grounded. The positive and negative logic level adjustment circuit includes resistors R3, R4, R5, R6, R7, and R8, capacitors C2, C3, and C4, and chip IC1. One end of resistor R4 and one end of resistor R6 are connected to ENA; the other end of resistor R6, one end of resistor R7, one end of resistor R5, and one end of capacitor C3 are connected together; the other end of resistor R4 and one end of resistor R3 are connected to the VIN+ power supply terminal; the other end of resistor R5 is connected to pin 3 of chip IC1, pin 10 of IC1 is left floating, one end of resistor C4 is connected to pin 9 (SS) of chip IC1; pin 8 of IC1 is connected to one end of resistor R8; the other ends of resistor R7, capacitor C3, capacitor C4, resistor R8, and pin 6 of chip IC1 are all grounded; one end of capacitor C2 is grounded, and the other end of capacitor C2 and the other end of resistor R3 are connected to pin 2 of chip IC1.

2. The switching power supply enable control circuit as described in claim 1, characterized in that, The diodes D1 and D2 are model 1N4148WT.

3. The switching power supply enable control circuit as described in claim 1, characterized in that, The MOSFET Q1 mentioned is model 2N7002T.

4. The switching power supply enable control circuit as described in claim 1, characterized in that, The Zener diode Z1 is model BZX584C5V1.

5. The switching power supply enable control circuit as described in claim 1, characterized in that, The resistors R1 and R2 have a resistance of 5.1KΩ, the capacitor C1 has a resistance of 0.1uF / 50V, the resistor R3 has a resistance of 200Ω, the resistor R4 has a resistance of 20KΩ, the resistor R5 has a resistance of 1KΩ, the resistor R6 has a resistance of 4.7KΩ, the resistor R7 has a resistance of 9.1KΩ, the resistor R8 has a resistance of 24KΩ, the capacitor C2 has a resistance of 0.47uF / 50V, the capacitor C3 has a resistance of 0.1uF / 50V, and the capacitor C4 has a resistance of 0.47uF / 50V.

6. The switching power supply enable control circuit as described in claim 1, characterized in that, The chip IC1 mentioned is model VPC2187B.

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