An enable control circuit

Abstract

The utility model discloses an enable control circuit, enable control circuit includes direct current bias circuit, return difference setting circuit and opposite phase impedance conversion circuit, the input end of direct current bias circuit is connected with external enable signal, and the output of direct current bias circuit is connected to the input of opposite phase impedance conversion circuit through return difference setting circuit, and the output of opposite phase impedance conversion circuit exports enable control signal, the utility model discloses through the switch tube of external end enable signal control circuit, exports enable control signal, and the voltage control of different switch tube conduction makes the return difference of external end enable signal opening and off voltage, solves and enables to control the voltage point of being close to not to shake the problem.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to an enable control circuit. Background Technology

[0002] With the development of new energy, 5G communication and other technologies, the power of related power supply switching products is also increasing. In order to facilitate customers to control the power supply to turn on / off, an exposed enable pin is usually designed that can be used to control the power supply to turn on / off of high-power switching products using a small power voltage source.

[0003] There are two common designs in the industry. The first is to directly connect the chip's enable pin to an external control pin via ESD protection. This design is simple in cost, and the control logic depends on the chip's enable voltage. The disadvantage is that the control voltage and hysteresis voltage are affected by the chip's logic, resulting in poor versatility. The second design uses a comparator to acquire and compare the external pin voltage with the control chip's enable pin. This design is highly versatile, and the hysteresis voltage is adjustable. The disadvantage is that it requires a chip and a relatively stable reference signal. Utility Model Content

[0004] To address the above problems, this invention proposes a simple enable control circuit based on discrete components that enables adjustable hysteresis without requiring an operational amplifier chip.

[0005] This utility model is achieved through the following technical solution:

[0006] This utility model provides an enable control circuit, which includes a DC bias circuit, a hysteresis setting circuit, and an inverting impedance transformation circuit;

[0007] An external enable signal is connected to the input terminal of the DC bias circuit, and the output terminal of the DC bias circuit is connected to the input terminal of the inverting impedance transformation circuit through the hysteresis setting circuit. The output terminal of the inverting impedance transformation circuit outputs an enable control signal.

[0008] Optionally, the DC bias circuit includes a first resistor and a second resistor. The first end of the first resistor is connected to an external enable signal, and the second end of the first resistor is connected to the power supply terminal through the second resistor. The second end of the first resistor is also connected to the input terminal of the hysteresis setting circuit.

[0009] Optionally, the hysteresis setting circuit includes a first switch, a second switch, a third resistor, a fourth resistor, and a fifth resistor. The control terminal of the first switch is connected to the output terminal of the DC bias circuit. The first terminal of the first switch is connected to the power supply terminal through the third resistor. The second terminal of the first switch is connected to ground through the fourth resistor. The first terminal of the first switch is connected to the control terminal of the second switch. The first terminal of the second switch is connected to the power supply terminal through the fifth resistor. The second terminal of the second switch is connected to ground through the fourth resistor. The first terminal of either the first switch or the first terminal of the second switch is connected to the input terminal of the inverting impedance transformation circuit 103.

[0010] Optionally, the inverting impedance transformation circuit 103 includes a sixth resistor and a third switch. The first end of the sixth resistor is connected to the output end of the hysteresis setting circuit, the second end of the sixth resistor is connected to the control end of the third switch, the first end of the third switch outputs an enable control signal, and the second end of the third switch is connected to ground.

[0011] Optionally, the first switching transistor is a bipolar transistor or a field-effect MOSFET.

[0012] Optionally, the second switching transistor is a bipolar transistor or a field-effect MOSFET.

[0013] Optionally, the third switching transistor is a bipolar transistor or a field-effect MOSFET.

[0014] This invention can change the turn-on and turn-off thresholds of the switching transistor in the hysteresis setting circuit by means of a hysteresis setting circuit, so that there is a hysteresis between the turn-on voltage and the turn-off voltage of the external enable signal, thus achieving hysteresis; at the same time, this invention can use all conventional discrete components, which is inexpensive and highly versatile. Attached Figure Description

[0015] Figure 1 This is a circuit schematic diagram of a first embodiment of the enable control circuit of this utility model;

[0016] Figure 2 This is a circuit schematic diagram of a second embodiment of the enable control circuit of this utility model;

[0017] Figure 3 This is a circuit schematic diagram of a third embodiment of the enable control circuit of this utility model;

[0018] Figure 4 This is a circuit diagram of the fourth embodiment of the enable control circuit of this utility model. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0020] This utility model embodiment provides an enable control circuit, which includes a DC bias circuit 101, a hysteresis setting circuit 102, and an inverting impedance transformation circuit 103.

[0021] The input terminal of the DC bias circuit 101 is connected to an external enable signal, and the output terminal of the DC bias circuit 101 is connected to the input terminal of the inverting impedance transformation circuit 103 through the hysteresis setting circuit 102. The output terminal of the inverting impedance transformation circuit 103 outputs an enable control signal.

[0022] The DC bias circuit 101 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to an external enable signal, and the second end of the first resistor R1 is connected to the power supply through the second resistor R2. The second end of the first resistor R1 is connected to the input of the hysteresis setting circuit 102.

[0023] In one embodiment, the hysteresis setting circuit 102 includes a first switch Q1, a second switch R2, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. The control terminal of the first switch Q1 is connected to the output terminal of the DC bias circuit 101. The first terminal of the first switch Q1 is connected to the power supply terminal through the third resistor R3. The second terminal of the first switch Q1 is connected to ground through the fourth resistor R4. The first terminal of the first switch Q1 is connected to the control terminal of the second switch Q2. The first terminal of the second switch Q2 is connected to the power supply terminal through the fifth resistor R5. The second terminal of the second switch Q2 is connected to ground through the fourth resistor. The first terminal of either the first switch Q1 or the first terminal of the second switch Q2 is connected to the input terminal of the inverting impedance transformation circuit 103.

[0024] In one embodiment, the inverting impedance transformation circuit 103 includes a sixth resistor R6 and a third switch Q3. The first end of the sixth resistor R6 is connected to the output end of the hysteresis setting circuit 102, the second end of the sixth resistor R6 is connected to the control end of the third switch Q3, the first end of the third switch Q3 outputs an enable control signal, and the second end of the third switch Q3 is connected to ground.

[0025] First Embodiment

[0026] Figure 1The diagram shown is a schematic of the first embodiment of an enable control circuit in this example; it includes a first switch Q1, a second switch Q2, a third switch Q3, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6.

[0027] One end of the first resistor R1 is connected to an external enable signal ON / OFF, and the other end is connected to one end of the second resistor R2 and the first end of the first switch Q1; the second end of the first switch Q1 is connected to one end of the third resistor R3 and the first end of the second switch Q2; the third end of the first switch Q1 is connected to one end of the fourth resistor R4 and the third end of the second switch Q2; the other end of the fourth resistor R4 is connected to ground; the other end of the second resistor R2 is connected to the other end of the third resistor R3, one end of the fifth resistor R5, and the power supply VCC; the other end of the fifth resistor R5 is connected to the second end of the second switch Q2 and one end of the sixth resistor R6; the other end of the sixth resistor R6 is connected to the first end of the third switch Q3; the third end of the third switch Q3 is connected to ground, and the second end is connected to the external enable signal EN that needs to be controlled.

[0028] When ON / OFF is initially high / floating, the first switch Q1 is turned on, the third resistor R3 and the fourth resistor R4 divide the voltage proportionally, the second switch Q2 should be in the off state, the second terminal of the second switch Q2 is high, which turns on the third switch Q3, and the EN enable signal is grounded.

[0029] When the ON / OFF voltage decreases from high, the turn-off voltage of the first switch Q1 must be less than the turn-on threshold of the first switch Q1, which is equal to the voltage divided by the third resistor R3 and the fourth resistor R4. When the first switch Q1 is turned off, its second terminal is at a high level, which turns on the second switch Q2. The voltage is divided by the fifth resistor R5 and the fourth resistor R4. At this time, the third switch Q3 should be in the off state, and the EN enable signal is released.

[0030] When the ON / OFF voltage rises from low, the turn-on voltage of the first switch Q1 must be greater than the turn-on threshold of the first switch Q1, which is the voltage divided proportionally by the fifth resistor R5 and the fourth resistor R4.

[0031] Therefore, by adjusting the third resistor R3, the fourth resistor R4, and the fifth resistor R5, the on / off threshold of the external ON / OFF voltage control product can be adjusted, thus achieving hysteresis in the control level.

[0032] Second Embodiment

[0033] Figure 2The diagram shown is a schematic of a second embodiment of an enable control circuit according to this embodiment; it includes a first switch Q1, a second switch Q2, a third switch Q3, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6.

[0034] One end of the first resistor R1 is connected to an external enable signal ON / OFF, and the other end is connected to one end of the second resistor R2 and the first terminal of the first switch Q1; the second terminal of the first switch Q1 is connected to one end of the third resistor R3, one end of the sixth resistor R6, and the first terminal of the second switch Q2; the third terminal of the first switch Q1 is connected to one end of the fourth resistor R4 and the third terminal of the second switch Q2; the other end of the fourth resistor R4 is connected to ground; the other end of the second resistor R2 is connected to the other end of the third resistor R3, one end of the fifth resistor R5, and the power supply VCC; the other end of the fifth resistor R5 is connected to the second terminal of the second switch Q2; the other end of the sixth resistor R6 is connected to the first terminal of the third switch Q3; the third terminal of the third switch Q3 is connected to ground, and the second terminal is connected to the external enable signal EN that needs to be controlled.

[0035] When ON / OFF is initially high or floating, the first switch Q1 is turned on, the third resistor R3 and the fourth resistor R4 divide the voltage proportionally, the second switch Q2 and the third switch Q3 should be in the off state, and the EN enable signal is released.

[0036] When the ON / OFF voltage decreases from high, the turn-off voltage of the first switch Q1 must be less than the turn-on threshold of the first switch Q1, which is equal to the voltage divided by the third resistor R3 and the fourth resistor R4. When the first switch Q1 is turned off, its second terminal is at a high level, which turns on the second switch Q2 and the third switch Q3. The voltage is divided by the fifth resistor R5 and the fourth resistor R4, and the third switch Q3 should be in the on state at this time, and the EN enable signal is grounded.

[0037] When the ON / OFF voltage rises from low, the turn-on voltage of the first switch Q1 must be greater than the turn-on threshold of the first switch Q1, which is the voltage divided proportionally by the fifth resistor R5 and the fourth resistor R4.

[0038] Therefore, by adjusting the third resistor R3, the fourth resistor R4, and the fifth resistor R5, the on / off threshold of the external ON / OFF voltage control product can be adjusted, thus achieving hysteresis in the control level.

[0039] Third Embodiment

[0040] Figure 3 The diagram shown is a schematic diagram of a third embodiment of the enable control circuit in this embodiment; compared with the second embodiment, only the first switching transistor Q1 is a transistor, and the overall control logic is the same.

[0041] The specific work is the same as in the second embodiment, and will not be repeated here.

[0042] Fourth embodiment

[0043] Figure 4 The diagram shown is a schematic diagram of the fourth embodiment of the enable control circuit in this embodiment; compared with the second embodiment, the first switch Q1, the first switch Q2, and the first switch Q3 are all transistors, and the overall control logic is the same.

[0044] The specific work is the same as in the second embodiment, and will not be repeated here.

[0045] The above embodiments are merely preferred embodiments of this utility model. It should be noted that the above preferred embodiments should not be considered as limitations on this utility model. Several improvements and modifications can be made without departing from the spirit and scope of this utility model, which are readily apparent from existing known technologies. These improvements and modifications should also be considered within the protection scope of this utility model, and will not be elaborated further here.

Claims

1. An enable control circuit, characterized in that: The enable control circuit includes a DC bias circuit, a hysteresis setting circuit, and an inverting impedance transformation circuit. An external enable signal is connected to the input terminal of the DC bias circuit, and the output terminal of the DC bias circuit is connected to the input terminal of the inverting impedance transformation circuit through the hysteresis setting circuit. The output terminal of the inverting impedance transformation circuit outputs an enable control signal.

2. The enable control circuit according to claim 1, characterized in that: The DC bias circuit includes a first resistor and a second resistor. The first end of the first resistor is connected to an external enable signal, and the second end of the first resistor is connected to the power supply terminal through the second resistor. The second end of the first resistor is also connected to the input terminal of the hysteresis setting circuit.

3. The enable control circuit according to claim 1, characterized in that: The hysteresis setting circuit includes a first switch, a second switch, a third resistor, a fourth resistor, and a fifth resistor. The control terminal of the first switch is connected to the output terminal of the DC bias circuit. The first terminal of the first switch is connected to the power supply terminal through the third resistor. The second terminal of the first switch is connected to ground through the fourth resistor. The first terminal of the first switch is connected to the control terminal of the second switch. The first terminal of the second switch is connected to the power supply terminal through the fifth resistor. The second terminal of the second switch is connected to ground through the fourth resistor. The first terminal of either the first switch or the first terminal of the second switch is connected to the input terminal of the inverting impedance transformation circuit.

4. The enable control circuit according to claim 1, characterized in that: The inverting impedance transformation circuit includes a sixth resistor and a third switch. The first end of the sixth resistor is connected to the output end of the hysteresis setting circuit, and the second end of the sixth resistor is connected to the control end of the third switch. The first end of the third switch outputs an enable control signal, and the second end of the third switch is connected to ground.

5. The enable control circuit according to claim 3, characterized in that: The first switching transistor is a bipolar transistor or a field-effect MOSFET.

6. The enable control circuit according to claim 3, characterized in that: The second switching transistor is a bipolar transistor or a field-effect MOSFET.

7. The enable control circuit according to claim 4, characterized in that: The third switching transistor is a bipolar transistor or a field-effect MOSFET.

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