Clamping protection circuit for adjusting output voltage

Abstract

The utility model discloses a clamping protection circuit used for adjusting output voltage. The clamping protection circuit comprises a clamping sub-circuit used for realizing voltage clamping, a switch sub-circuit used for realizing on-off of current, a voltage detection sub-circuit used for detecting the output voltage, and an energy storage filtering sub-circuit used for storing electric energy and filtering. The input end of the clamping sub-circuit is connected with the input end of a whole vehicle power source, the output end of the clamping sub-circuit is connected with the input end of the switch sub-circuit and the input end of the voltage detection sub-circuit, and the output end of the switch sub-circuit and the output end of the voltage detection sub-circuit are connected in parallel and then connected with the input end of the input end of the energy storage filtering sub-circuit and the input end of the first-stage power source chip. And when the output voltage of the switch sub-circuit is greater than a preset voltage threshold value in the voltage detection sub-circuit, the switch sub-circuit is disconnected, and cycle work is started.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a clamping protection circuit for regulating output voltage. Background Technology

[0002] In automotive electronics, the requirements of OEMs are increasing (e.g., 36V normal operation, 48V to maintain operation for 5 minutes).

[0003] like Figure 1 As shown, existing technology uses a TVS diode as a protective element between the primary power chip and the vehicle power input. However, since the clamping voltage of the TVS diode is proportional to the breakdown voltage, and the clamping voltage is about 1 / 3 higher than the breakdown voltage, the breakdown voltage may not meet the requirements when a suitable clamping voltage is selected, and vice versa. Especially during EMC testing (7637-5A), the test voltage is very high. If the output voltage is not adjusted, it will damage the primary power chip. However, existing technology does not allow adjustment of the output voltage (the voltage input to the primary power chip), thus failing to meet Class A requirements and consequently failing to meet customer requirements. Summary of the Invention

[0004] To address the technical problem that existing technologies cannot adjust the output voltage of the vehicle power supply, this invention proposes a clamping protection circuit for adjusting the output voltage.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A clamping protection circuit for regulating output voltage includes a clamping sub-circuit for voltage clamping, a switching sub-circuit for current switching, a voltage detection sub-circuit for detecting output voltage, and an energy storage filtering sub-circuit for filtering.

[0007] The input terminal of the clamping sub-circuit is connected to the vehicle power input, and the output terminal of the clamping sub-circuit is connected to the input terminal of the switching sub-circuit and the input terminal of the voltage detection sub-circuit respectively. The output terminals of the switching sub-circuit and the voltage detection sub-circuit are connected in parallel and then connected to the input terminal of the energy storage filter sub-circuit and the input terminal of the primary power chip.

[0008] When the output voltage of the switching sub-circuit is greater than the preset voltage threshold in the voltage detection sub-circuit, the switching sub-circuit is disconnected; when the output voltage of the switching sub-circuit is less than the preset voltage threshold in the voltage detection sub-circuit, the switching sub-circuit is turned on.

[0009] Preferably, the clamping sub-circuit includes a TVS diode, a first capacitor, and a second capacitor.

[0010] The vehicle power input terminal is connected to one end of the TVS diode and one end of the first capacitor, respectively. The other end of the first capacitor is connected to one end of the second capacitor. The other end of the TVS diode and the other end of the second capacitor are connected in parallel and then grounded.

[0011] Preferably, the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are 470nF.

[0012] Preferably, the switching sub-circuit includes a first switch and a first diode:

[0013] The vehicle power input terminal, one end of the TVS diode, and one end of the first capacitor are connected in parallel and then connected to the source of the first switch and the negative terminal of the first diode, respectively. The gate of the first switch and the positive terminal of the first diode are connected in parallel and then connected to the control terminal of the voltage detection sub-circuit. The drain of the first switch is connected to the input terminal of the first-stage power chip.

[0014] Preferably, the first switch is a PMOS transistor.

[0015] Preferably, the voltage detection sub-circuit includes a second switch, a third switch, and a second diode:

[0016] The vehicle power input terminal, one end of the TVS diode, and one end of the first capacitor are connected in parallel and then connected to one end of the first resistor and one end of the third resistor, respectively. The other end of the first resistor is connected to one end of the second resistor, the collector of the second switch, and the base of the third switch, respectively. The other end of the second resistor is grounded.

[0017] The other end of the third resistor is connected in parallel with the gate of the first switch and then connected to one end of the fourth resistor. The other end of the fourth resistor is connected to the collector of the third switch, and the emitter of the third switch is grounded.

[0018] The emitter of the second switch is grounded; the base of the second switch is connected to one end of the third capacitor and one end of the fifth resistor, and the other end of the third capacitor is grounded; the other end of the fifth resistor is connected to the anode of the second diode and one end of the sixth resistor, and the other end of the sixth resistor is grounded; the cathode of the second diode is connected in parallel with the drain of the first switch and then connected to the input terminal of the first-stage power supply chip.

[0019] Preferably, both the second switch and the third switch are NPN transistors.

[0020] Preferably, the energy storage filter sub-circuit includes a fourth capacitor and a first polarity capacitor:

[0021] The negative terminal of the second diode is connected in parallel with the drain of the first switch and then connected to one end of the fourth capacitor and one end of the first polarized capacitor, respectively. The other end of the fourth capacitor is grounded; the other end of the first polarized capacitor is grounded.

[0022] Preferably, the capacitance of the fourth capacitor is 470nF; the capacitance of the first polarity capacitor is 220uF.

[0023] In summary, by adopting the above technical solution, compared with the prior art, this utility model has at least the following beneficial effects:

[0024] 1) It can effectively convert the normal input high voltage into low voltage, meet the voltage input range requirements of the first-level power supply chip, and avoid chip damage caused by high voltage input;

[0025] 2) When the input voltage is too high, the output voltage amplitude can be adjusted by regulating the voltage through the second diode;

[0026] 3) It enables the fulfillment of customer requirements through simple hardware circuit design. Attached image description:

[0027] Figure 1 This is a schematic diagram of an existing voltage clamping circuit.

[0028] Figure 2 This is a schematic diagram of a clamping protection circuit for adjusting output voltage, as exemplarily provided by the present invention.

[0029] Figure 3 This is a schematic diagram illustrating the principle of a clamping protection circuit for adjusting output voltage, as exemplarily provided by this utility model. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments and specific implementation methods. However, it should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0031] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0032] like Figure 2 As shown, this utility model provides a clamping protection circuit for regulating output voltage, including a clamping sub-circuit for voltage clamping, a switching sub-circuit for current switching, a voltage detection sub-circuit for detecting output voltage, and an energy storage and filtering sub-circuit for storing electrical energy and filtering.

[0033] The input terminal of the clamping sub-circuit is connected to the vehicle power input. The output terminal of the clamping sub-circuit is connected to the input terminal of the switching sub-circuit and the input terminal of the voltage detection sub-circuit, respectively. The output terminals of the switching sub-circuit and the voltage detection sub-circuit are connected in parallel and then connected to the input terminal of the energy storage filter sub-circuit and the input terminal of the primary power chip.

[0034] When the output voltage of the switching sub-circuit is greater than or equal to the preset voltage threshold in the voltage detection sub-circuit, the switching sub-circuit is opened, and the voltage input to the vehicle power supply cannot reach the first-level power chip; when the output voltage of the switching sub-circuit is less than the preset voltage threshold in the voltage detection sub-circuit, the switching sub-circuit remains closed, so that the voltage input to the vehicle power supply reaches the first-level power chip.

[0035] like Figure 3 As shown, in this embodiment, the clamping sub-circuit includes a TVS (transient voltage suppressor) TVS1, a first capacitor C1, and a second capacitor C2.

[0036] The vehicle power input terminal (POWER_IN) is connected to one end of TVS transistor TVS1 and one end of first capacitor C1, respectively. The other end of first capacitor C1 is connected to one end of second capacitor C2. The other ends of TVS transistor TVS1 and second capacitor C2 are connected in parallel and then grounded.

[0037] The capacitance values ​​of the first capacitor C1 and the second capacitor C2 are 470nF, but can be adjusted according to actual conditions to improve voltage withstand.

[0038] The clamping sub-circuit mainly uses TVS transistor TVS1 to clamp the high voltage input to the vehicle power input terminal, thereby protecting the switching sub-circuit and the voltage detection sub-circuit.

[0039] In this embodiment, the switching sub-circuit includes a first switch Q1 (which may be a PMOS transistor) and a first diode ZD1:

[0040] The vehicle power input terminal, one end of TVS transistor TVS1, and one end of first capacitor C1 are connected in parallel and then connected to the source of first switch Q1 and the negative terminal of first diode ZD1 (which is used to ensure the normal conduction of MOSFET Q1). The gate of first switch Q1 and the positive terminal of first diode ZD1 are connected in parallel and then connected to the control terminal of voltage detection sub-circuit. The drain of first switch Q1 is connected to the input terminal of first-stage power chip.

[0041] In this embodiment, the on / off state of the first switch Q1 is controlled by the control terminal of the voltage detection sub-circuit.

[0042] In this embodiment, the voltage detection sub-circuit includes a second switch Q2, a third switch Q3, and a second diode ZD2:

[0043] The vehicle power input terminal, one end of TVS transistor TVS1, and one end of first capacitor C1 are connected in parallel and then connected to one end of first resistor R1 and one end of third resistor R3, respectively. The other end of first resistor R1 is connected to one end of second resistor R2, the collector of second switch Q2 (NPN transistor), and the base of third switch Q3 (NPN transistor), respectively. The other end of second resistor R2 is grounded. The resistance of first resistor R1 is 10KΩ, the resistance of second resistor R2 is 100KΩ, and the resistance of third resistor R3 is 47KΩ.

[0044] The other end of the third resistor R3 is connected in parallel with the gate of the first switch Q1 and then connected to one end of the fourth resistor R4. The other end of the fourth resistor R4 is connected to the collector of the third switch Q3, and the emitter of the third switch Q3 is grounded. The resistance of the fourth resistor R4 is 68KΩ.

[0045] The emitter of the second switch Q2 is grounded; the base of the second switch Q2 is connected to one end of the third capacitor C3 and one end of the fifth resistor R5, with the other end of the third capacitor C3 grounded; the other end of the fifth resistor R5 is connected to the anode of the second diode ZD2 and one end of the sixth resistor R6, with the other end of the sixth resistor R6 grounded; the cathode of the second diode ZD2 is connected in parallel with the drain of the first switch Q1 and then connected to the input terminal of the first-stage power supply chip. The capacitance of the third capacitor C3 is 1nF, and the resistances of the fifth resistor R5 and the sixth resistor R6 are both 10KΩ.

[0046] In this embodiment, the working principle of the voltage detection sub-circuit controlling the on / off state of the switch sub-circuit is as follows:

[0047] (1) When the output voltage of the switch sub-circuit is greater than the voltage regulation voltage of the second diode ZD2 (the second switch Q2 needs a voltage difference of 0.6V to turn on Q2, and it must be at least higher than 0.6V to meet the conduction condition of the transistor Q2, that is, the output voltage of the switch sub-circuit - the voltage regulation voltage of the second diode ZD2 ≥ 0.6V), the base of the second switch Q2 is energized, the second switch Q2 is turned on, and the voltage input to the vehicle is grounded through the second switch Q2, so that the voltage is not passed through the first switch Q1 and the third switch Q3, that is, the first switch Q1 and the third switch Q3 are in the off state at this time;

[0048] (2) When the first switch Q1 is turned off, the output voltage of the switch sub-circuit will decrease. When it decreases to below the regulated voltage of ZD2 (i.e., when the output voltage is less than or equal to the regulated voltage of ZD2), ZD2 stops working, the base of the second switch Q2 is de-energized, the second switch Q2 is turned off, the base of the third switch Q3 is energized, the third switch Q3 is turned on, thereby energizing the gate of the first switch Q1 and turning on the first switch Q1, so that the voltage input to the whole vehicle can smoothly enter the first-level power chip.

[0049] The above processes (1) and (2) can be repeated indefinitely, thereby clamping the output voltage of the switching sub-circuit to around the regulated value of ZD2. That is, by freely setting the regulated value of the second diode ZD2, the output voltage can be adjusted to meet the voltage requirements of the first-level power chip and avoid damage to the chip caused by high voltage input.

[0050] In this embodiment, the energy storage filter sub-circuit includes a fourth capacitor C4 and a first polarity capacitor EC1 (mainly used for filtering):

[0051] The negative terminal of the second diode ZD2 is connected in parallel with the drain of the first switch Q1 and then connected to one end of the fourth capacitor C4 and one end of the first polarized capacitor EC1, respectively. The other end of the fourth capacitor C4 is grounded; the other end of the first polarized capacitor EC1 is grounded.

[0052] The capacitance of the fourth capacitor C4 is 470nF, which can be adjusted according to the actual circuit conditions; the capacitance of the first polarity capacitor EC1 is 220uF, which can be adjusted according to the actual circuit conditions.

[0053] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A clamp protection circuit for regulating an output voltage, characterized by The application relates to a voltage regulator circuit, which comprises a clamping subcircuit for realizing voltage clamping, a switching subcircuit for realizing current on-off, a voltage detection subcircuit for detecting an output voltage and an energy storage filter subcircuit for filtering; The input end of the clamping subcircuit is connected with a vehicle power input, the output end of the clamping subcircuit is connected with the input end of the switching subcircuit and the input end of the voltage detection subcircuit respectively, the output end of the switching subcircuit and the output end of the voltage detection subcircuit are connected with the input end of the energy storage filter subcircuit and the input end of a primary power chip in parallel; When the output voltage of the switching subcircuit is greater than a preset voltage threshold in the voltage detection subcircuit, the switching subcircuit is turned off; when the output voltage of the switching subcircuit is less than the preset voltage threshold in the voltage detection subcircuit, the switching subcircuit is turned on.

2. A clamp protection circuit for regulating an output voltage as defined in claim 1, wherein The clamping subcircuit comprises a TVS tube, a first capacitor and a second capacitor; The vehicle power input is connected with one end of the TVS tube and one end of the first capacitor, the other end of the first capacitor is connected with one end of the second capacitor, and the other end of the TVS tube and the other end of the second capacitor are connected with the ground in parallel.

3. A clamp protection circuit for regulating an output voltage as defined in claim 2, wherein The capacitance values of the first capacitor C1 and the second capacitor C2 are 470nF.

4. The clamp protection circuit for regulating an output voltage as defined in claim 1, wherein The switching subcircuit comprises a first switch and a first diode; The vehicle power input, one end of the TVS tube and one end of the first capacitor are connected with the source electrode of the first switch and the negative electrode of the first diode in parallel respectively, the gate electrode of the first switch and the positive electrode of the first diode are connected with the control end of the voltage detection subcircuit in parallel, and the drain electrode of the first switch is connected with the input end of the primary power chip.

5. A clamp protection circuit for regulating an output voltage as defined in claim 4, wherein The first switch is a PMOS tube.

6. The clamp protection circuit for regulating an output voltage as defined in claim 1, wherein The voltage detection subcircuit comprises a second switch, a third switch and a second diode; The vehicle power input, one end of the TVS tube and one end of the first capacitor are connected with one end of the first resistor and one end of the third resistor in parallel respectively, the other end of the first resistor is connected with one end of the second resistor, the collector electrode of the second switch and the base electrode of the third switch respectively, and the other end of the second resistor is connected with the ground; The other end of the third resistor and the gate electrode of the first switch are connected with one end of the fourth resistor in parallel, the other end of the fourth resistor is connected with the collector electrode of the third switch, and the emitter electrode of the third switch is connected with the ground; The emitter electrode of the second switch is connected with the ground, the base electrode of the second switch is connected with one end of the third capacitor and one end of the fifth resistor respectively, the other end of the third capacitor is connected with the ground, the other end of the fifth resistor is connected with the positive electrode of the second diode and one end of the sixth resistor respectively, the other end of the sixth resistor is connected with the ground, and the negative electrode of the second diode and the drain electrode of the first switch are connected with the input end of the primary power chip in parallel.

7. A clamp protection circuit for regulating an output voltage as defined in claim 6, wherein The second switch and the third switch are both NPN triodes.

8. The clamp protection circuit for regulating an output voltage as defined in claim 1, wherein The energy storage filter subcircuit comprises a fourth capacitor and a first polarity capacitor; The negative electrode of the second diode and the drain electrode of the first switch are connected with one end of the fourth capacitor and one end of the first polarity capacitor respectively, and the other end of the fourth capacitor is connected with the ground; and the other end of the first polarity capacitor is connected with the ground.

9. A clamp protection circuit for regulating an output voltage as defined in claim 8, wherein The capacitance value of the fourth capacitor is 470nF, and the capacitance value of the first polarity capacitor is 220uF.

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