CN212163169U - Automobile power signal switch circuit - Google Patents
Automobile power signal switch circuit Download PDFInfo
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- CN212163169U CN212163169U CN202021179502.2U CN202021179502U CN212163169U CN 212163169 U CN212163169 U CN 212163169U CN 202021179502 U CN202021179502 U CN 202021179502U CN 212163169 U CN212163169 U CN 212163169U
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Abstract
The utility model provides a car power signal switch circuit, include: the constant power supply circuit comprises a constant power supply input end, a functional power supply input end, a first diode, an RC energy storage circuit, a first resistor, a second resistor, a first switch tube, a third resistor, a second switch tube, a protection circuit, an anti-reverse connection circuit and a functional power supply output. The utility model discloses an automobile power signal switch circuit can obtain the control circuit who stabilizes output voltage from other invariable power through gathering the PWM signal, and its reaction rate and interference immunity ability all have outstanding advantage to low cost realizes convenient and reliable.
Description
Technical Field
The utility model relates to a switch circuit field especially relates to an automobile power signal switch circuit.
Background
The automobile power supply is a battery and a generator for dual power supply, when the automobile power supply reaches automobile electric control parts under the control of a BCM (automobile body controller), if the automobile electric control parts are continuous power supplies, the controller can normally work, but when the BCM supplies PWM (generally about 100 HZ) power supplies to the automobile electric control parts, some automobile electric control parts cannot normally work. If the host factory can not modify the BCM control mode for some reason, the embarrassment that the electric control parts of the automobile can not work normally is caused.
Disclosure of Invention
To not enough among the above-mentioned prior art, the utility model provides an automobile power signal switch circuit can obtain the control circuit who stabilizes output voltage from other constant power sources through gathering the PWM signal, and its reaction rate and interference immunity ability all have outstanding advantage to low cost realizes convenient and reliable.
In order to achieve the above object, the utility model provides an automobile power signal switch circuit, include:
a constant power input terminal;
a functional power supply input terminal;
the anode of the first diode is connected with the functional power supply input end;
an RC energy storage circuit; the RC energy storage circuit is connected with the cathode of the first diode;
the first resistor is connected between the cathode of the first diode and a grounding end;
the first end of the second resistor is connected with the RC energy storage circuit;
the grid electrode of the first switch tube is connected with the second end of the second resistor, and the source electrode of the first switch tube is connected with the cathode of the first diode;
the first end of the third resistor is connected with the drain electrode of the first switching tube;
the grid electrode of the second switch tube is connected with the second end of the third resistor, and the drain electrode of the second switch tube is connected with the constant power supply input end;
the protection circuit is connected between the grid electrode of the second switching tube and the input end of the constant power supply;
the reverse connection preventing circuit is connected between the functional power supply input end and the source electrode of the second switch tube; and
and the functional power supply output end is connected with the source electrode of the second switch tube.
Preferably, the RC tank circuit comprises:
the anode of the second diode is connected with the cathode of the first diode;
a first end of the fourth resistor is connected with the anode of the second diode, and a second end of the fourth resistor is connected with the first end of the second resistor;
a fifth resistor; and
and the fifth resistor and the capacitor are connected in parallel between the first end of the second resistor and the ground terminal.
Preferably, the protection circuit comprises a sixth resistor and a third diode, and the sixth resistor and the third diode are connected in parallel between the constant power input end and the gate of the second switching tube; and the anode of the third diode is connected with the grid electrode of the second switching tube, and the cathode of the third diode is connected with the constant power supply input end.
The utility model discloses owing to adopted above technical scheme, make it have following beneficial effect:
1. stable output voltage is obtained from other constant power supplies by collecting PWM signals, the response speed and the anti-interference capability of the constant output voltage have outstanding advantages, the cost is low, and the realization is convenient and reliable;
2. when the input end of the functional power supply is at high level, the power switch circuit selects to supply power by the functional power supply, and when the functional power supply is suspended or at low level, the power switch circuit selects to supply power by the constant power supply. The power supply mode can supply high-power electric loads, and is small in heat productivity and high in working efficiency.
3. The problem of BCM false alarm can not be caused (BCM only can detect whether the output current meets the standard when outputting the functional power supply), and when the BCM outputs the functional power supply, the power supply switch circuit selects the functional power supply sent by the BCM for power supply.
4. The time of the power supply output by the power supply switch circuit is short, and when the functional power supply is input, continuous functional power supply output can be obtained at the output end of the power supply switch circuit immediately.
5. The power switch circuit has strong anti-interference capability, can resist the electromagnetic interference of a power supply and space of an automobile grade, and has stable and reliable performance.
6. When the input end of the functional power supply is disconnected, the output end of the functional power supply of the power supply switching circuit is timely disconnected after the short time delay of ms level.
Drawings
Fig. 1 is a circuit diagram of an automotive power signal switching circuit according to an embodiment of the present invention;
fig. 2 is a comparison diagram of the constant power supply, the functional power supply input and the functional power supply output signal according to the embodiment of the present invention.
Detailed Description
The following description of the preferred embodiments of the present invention will be given with reference to the accompanying drawings 1 and 2, and will make the functions and features of the present invention better understood.
Referring to fig. 1, an embodiment of the present invention provides an automobile power signal switch circuit, including: a constant power supply input end P1, a functional power supply input end P2, a first diode D1, an RC energy storage circuit 1, a first resistor R1, a second resistor R4, a first switch tube Q2, a third resistor R5, a second switch tube Q1, a protection circuit 2, an anti-reverse connection circuit 3 and a functional power supply output end P3; the anode of the first diode D1 is connected with the functional power input end P2; the RC energy storage circuit 1 is connected with the cathode of a first diode D1; the first resistor R1 is connected between the cathode of the first diode D1 and a ground terminal; a first end of the second resistor R4 is connected with the RC energy storage circuit 1; the gate of the first switch tube Q2 is connected to the second end of the second resistor R4, and the source of the first switch tube Q2 is connected to the cathode of the first diode D1; a first end of the third resistor R5 is connected with the drain of the first switch tube Q2; the grid electrode of the second switching tube Q1 is connected with the second end of the third resistor R5, and the drain electrode of the second switching tube Q1 is connected with the constant power supply input end P1; the protection circuit 2 is connected between the grid of the second switching tube Q1 and the constant power input end P1; the anti-reverse connection circuit 3 is connected between the functional power supply input end P2 and the source electrode of the second switch tube Q1; the functional power output terminal P3 is connected to the source of the second switch transistor Q1.
Wherein, RC tank circuit 1 includes: a second diode D2, a fourth resistor R2, a fifth resistor R3, and a capacitor C1. The anode of the second diode D2 is connected with the cathode of the first diode D1; a first end of the fourth resistor R2 is connected to the anode of the second diode D2, and a second end of the fourth resistor R2 is connected to a first end of the second resistor R4; the fifth resistor R3 and the capacitor C1 are connected in parallel between the first end of the second resistor R4 and the ground terminal.
In this embodiment, the protection circuit 2 includes a sixth resistor R6 and a third diode D3, the sixth resistor R6 and the third diode D3 are connected in parallel between the constant power input terminal P1 and the gate of the second switch Q1; the anode of the third diode D3 is connected to the gate of the second switch Q1, and the cathode of the third diode D3 is connected to the constant power input terminal P1.
The utility model discloses a car power signal switch circuit, second diode D2, fourth resistance R2, fifth resistance R3 and electric capacity C1 constitute RC energy storage circuit 1, when the PWM signal of functional power input end P2 arrives, convert the PWM signal into stable direct current signal through the circuit and switch on first switch tube Q2, third diode D3's existence makes RC energy storage circuit 1's the return circuit that discharges only one, through second resistance R4, first switch tube Q2 discharges, can reduce the parameter of RC in the RC energy storage circuit 1 greatly, reduce the device encapsulation.
Due to the existence of the RC energy storage circuit 1, the impact interference of power high pulse or ESD coexisting when the functional power is input can be resisted.
The sixth resistor R6 and the third diode D3 are used to protect the second switch Q1 (for example, the second switch Q1 is a PMOS transistor).
The fourth resistor R2 and the fifth resistor R3 form a voltage divider circuit, and since the conducting voltage of the first switch Q2 is low, in order to resist the voltage increase caused by the interference of the functional power input terminal P2 or other reasons, a low voltage signal lower than a certain level needs to be filtered by the voltage divider circuit.
The second resistor R4 is a series resistor of the discharge circuit of the filter circuit, and determines how fast the first switch Q2 is turned off.
The reverse connection preventing circuit 3 is used for preventing the reverse flow power supply from triggering BCM alarm when the functional power supply has voltage output but the functional power supply has no high voltage input.
When negative pulse occurs at the functional power input end P1, the B point is still at high level due to the filtering energy storage, which may make the negative pulse of the first switch tube Q2 be instantaneously misconducted. The presence of the second diode D2 effectively blocks the intrusion of the negative pulse.
The first switch tube Q2 and the second switch tube Q1 may adopt any controlled switch tubes, for example, in this embodiment, the first switch tube Q2 adopts a triode, and the second switch tube Q1 adopts a MOS tube.
Referring to fig. 1 and fig. 2, for a high-power load, a large current flows through the first power supply branch 4 and the second power supply branch 5 to generate heat loss, but since the first power supply branch 4 and the second power supply branch 5 work alternately, heat cannot be concentrated on one device, and the heat generated by the power supply open tube can be greatly relieved.
When the functional power input of the functional power input terminal P2 is at a high level, the first switch tube Q2 will not conduct due to the failure of the conduction condition, the functional power input passes through the reverse connection prevention circuit 3 and is output from the functional power output terminal P3, and the voltage difference between the functional power input terminal P2 and the functional power output terminal P3 is the voltage drop of the reverse connection prevention circuit 3.
When the functional power input at the functional power input terminal P2 is at a low level or floating in the PWM cycle, the first switch Q2 starts to be turned on under the action of the RC energy storage circuit 1, and simultaneously, the second switch Q1 is also turned on to output the functional power. The voltage difference between the functional power input terminal P2 and the functional power output terminal P3 is the voltage difference of the second switching tube Q1.
When the input of the functional power supply is restored to the high level, the second switch tube Q1 and the first switch tube Q2 are immediately cut off, and then the input of the functional power supply passes through the reverse connection preventing circuit 3 and is output from the output end P3 of the functional power supply, so that the tracking speed is very timely.
When the functional power input is a continuous low level or floating, when the discharge of the RC energy storage circuit 1 is finished (in fig. 2, the delay time can be determined by parameters of the fourth resistor R2, the fifth resistor R3, the capacitor C1, and the second resistor R4), the second switch tube Q1 and the first switch tube Q2 are turned off, and the output of the functional power output terminal P3 is turned off.
The present invention has been described in detail with reference to the embodiments shown in the drawings, and those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details of the embodiments should not be construed as limitations of the invention, which are intended to be covered by the following claims.
Claims (3)
1. An automotive power signal switching circuit, comprising:
a constant power input terminal;
a functional power supply input terminal;
the anode of the first diode is connected with the functional power supply input end;
an RC energy storage circuit; the RC energy storage circuit is connected with the cathode of the first diode;
the first resistor is connected between the cathode of the first diode and a grounding end;
the first end of the second resistor is connected with the RC energy storage circuit;
the grid electrode of the first switch tube is connected with the second end of the second resistor, and the source electrode of the first switch tube is connected with the cathode of the first diode;
the first end of the third resistor is connected with the drain electrode of the first switching tube;
the grid electrode of the second switch tube is connected with the second end of the third resistor, and the drain electrode of the second switch tube is connected with the constant power supply input end;
the protection circuit is connected between the grid electrode of the second switching tube and the input end of the constant power supply;
the reverse connection preventing circuit is connected between the functional power supply input end and the source electrode of the second switch tube; and
and the functional power supply output end is connected with the source electrode of the second switch tube.
2. The automotive power signal switching circuit of claim 1, wherein the RC tank circuit comprises:
the anode of the second diode is connected with the cathode of the first diode;
a first end of the fourth resistor is connected with the anode of the second diode, and a second end of the fourth resistor is connected with the first end of the second resistor;
a fifth resistor; and
and the fifth resistor and the capacitor are connected in parallel between the first end of the second resistor and the ground terminal.
3. The automotive power signal switching circuit of claim 2, wherein the protection circuit includes a sixth resistor and a third diode, the sixth resistor and the third diode being connected in parallel between the constant power input terminal and the gate of the second switching transistor; and the anode of the third diode is connected with the grid electrode of the second switching tube, and the cathode of the third diode is connected with the constant power supply input end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021179502.2U CN212163169U (en) | 2020-06-23 | 2020-06-23 | Automobile power signal switch circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021179502.2U CN212163169U (en) | 2020-06-23 | 2020-06-23 | Automobile power signal switch circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212163169U true CN212163169U (en) | 2020-12-15 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021179502.2U Active CN212163169U (en) | 2020-06-23 | 2020-06-23 | Automobile power signal switch circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212163169U (en) |
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2020
- 2020-06-23 CN CN202021179502.2U patent/CN212163169U/en active Active
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