Low-cost reliable electronic switch protection circuit and electric moped

Abstract

The utility model discloses a low-cost and reliable electronic switch protection circuit and an electric moped. The circuit comprises a resistor R10, one end of the resistor R10 is connected with a processor, the other end of the resistor R10 is connected with a positive electrode of a diode D1 and one end of a resistor R6, the other end of the resistor R6 is connected with a base electrode of a triode Q2, an emitting electrode of the triode Q2 is grounded, and a collecting electrode of the triode Q2 is connected with one end of a current limiting resistor. The other end of the current-limiting resistor is connected with one end of the resistor R1 and the control end of the switch tube Q1, the input end of the switch tube Q1 and the other end of the resistor R1 are both connected with the positive electrode VDD of the power supply, and the output end of the switch tube Q1 is connected with the negative electrode of the diode D1 and the load. According to the utility model, the timeliness of circuit action is improved, and when a short-circuit state occurs, the output can be closed in time, so that the switching circuit is not invalid; and when the load relieves the short-circuit state, the circuit automatically recovers the normal working state.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power-assisted vehicles, and in particular to a low-cost and reliable electronic switch protection circuit and an electric power-assisted vehicle. Background Art

[0002] The electronic switch circuit is a commonly used control circuit on electric power-assisted bicycles. The main controller controls the operation of components such as headlights and horns through the electronic switch circuit. The electronic switch circuit in the prior art generally collects the state of the output voltage through the feedback circuit, and feeds back the collected output voltage to the processor. The processor can judge whether the current load is short-circuited based on the fed-back output voltage. When the load is short-circuited, the microprocessor controls the electronic switch to disconnect. This method requires the polling speed of the AD converter to be fast enough, and it is necessary to filter abnormal data such as ripple, external interference signals, etc. through software algorithms in order to reliably judge whether the load is short-circuited. It also takes up processor time and relies on processor control, which also has a certain lag. Utility Model Content

[0003] The purpose of the utility model is to provide a low-cost and reliable electronic switch protection circuit and an electric power-assisted vehicle in view of the deficiencies in the prior art.

[0004] To achieve the above-mentioned purpose, in a first aspect, the utility model provides a low-cost and reliable electronic switch protection circuit, comprising a resistor R10 having one end connected to a processor, the other end of the resistor R10 being respectively connected to the positive electrode of a diode D1 and one end of a resistor R6, the other end of the resistor R6 being connected to the base of a transistor Q2, the emitter of the transistor Q2 being grounded, and the collector thereof being connected to one end of a current-limiting resistor, the other end of the current-limiting resistor being connected to one end of the resistor R1 and a control end of a switch tube Q1, the input end of the switch tube Q1 and the other end of the resistor R1 being both connected to a positive power supply VDD, and the output end of the switch tube Q1 being respectively connected to a negative electrode of the diode D1 and a load.

[0005] Furthermore, the current limiting resistor includes a resistor R2 and a resistor R3 connected in parallel.

[0006] Furthermore, the output end of the switch tube Q1 is also connected to a voltage divider feedback circuit, which includes a resistor R4 with one end connected to the output end of the switch tube Q1, the other end of the resistor R4 is respectively connected to one end of a resistor R5 and a resistor R7, the other end of the resistor R5 is used to connect to the processor, and the other end of the resistor R7 is grounded.

[0007] Furthermore, the resistor R7 is also connected in parallel with a capacitor C1.

[0008] Furthermore, the other end of the resistor R6 is also connected to one end of the resistor R8, and the other end of the resistor R8 is grounded.

[0009] Furthermore, the switch tube Q1 includes a triode and a MOS tube.

[0010] In a second aspect, the utility model provides an electric power-assisted bicycle instrument, comprising the above-mentioned low-cost and reliable electronic switch protection circuit.

[0011] Beneficial effects: 1. The utility model improves the timeliness of circuit action. When a short circuit occurs, the output can be turned off in time, so as not to cause the switch circuit to fail;

[0012] 2. When the load is released from the short-circuit state, the circuit automatically returns to normal working state. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of a low-cost and reliable electronic switch protection circuit according to an embodiment of the utility model. DETAILED DESCRIPTION

[0014] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. The embodiments are implemented based on the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0015] like Figure 1 As shown, the embodiment of the utility model provides a low-cost and reliable electronic switch protection circuit, including a resistor R10, one end of which is connected to a processor, and the processor includes a single-chip microcomputer. The other end of the resistor R10 is connected to the positive electrode of the diode D1 and one end of the resistor R6 respectively, the other end of the resistor R6 is connected to the base of the transistor Q2, the emitter of the transistor Q2 is grounded, and its collector is connected to one end of the current limiting resistor, the other end of the current limiting resistor is connected to one end of the resistor R1 and the control end of the switch tube Q1, the input end of the switch tube Q1 and the other end of the resistor R1 are both connected to the positive electrode VDD of the power supply, and the output end of the switch tube Q1 is connected to the negative electrode of the diode D1, the load and the voltage divider feedback circuit respectively.

[0016] The current limiting resistor in the embodiment of the utility model includes a resistor R2 and a resistor R3, and the resistor R2 and the resistor R3 are connected in parallel.

[0017] In order to retain the original output voltage feedback function, the output end of the switch tube Q1 of the embodiment of the utility model can also be connected to a voltage-dividing feedback circuit, which includes resistors R4, R5 and R7. One end of the resistor R4 is connected to the output end of the switch tube Q1, and the other end of the resistor R4 is connected to one end of the resistor R5 and one end of the resistor R7 respectively. The other end of the resistor R5 is used to connect to the processor to feed back the voltage at the output end of the switch tube Q1 to the processor, and the other end of the resistor R7 is grounded. The resistor R7 is preferably connected in parallel with a capacitor C1.

[0018] The other end of the resistor R6 in the embodiment of the utility model is also connected to one end of the resistor R8, and the other end of the resistor R8 is grounded.

[0019] The switch tube Q1 of the embodiment of the utility model includes a triode and a MOS tube. Figure 1 The switch tube Q1 shown in the figure is a triode, the emitter of the triode is the input terminal, and the collector of the triode is the output terminal. When the switch tube Q1 adopts an NMOS tube, its drain is the input terminal and the source is the output terminal.

[0020] Working principle:

[0021] Working state 1: Before the system is powered on, if the load resistor R9 is in a short-circuit state, the load resistor R9 will be short-circuited to the ground. At the time of power-on, the voltage of the LOADER node is 0V, and the node connected by resistors R10 and R6 is clamped to about 0.7V through diode D1. After the clamping voltage is divided by resistors R6 and R8, it cannot turn on the transistor Q2. At this time, if the processor gives a high level (3.3V or 5V) through PWR_ON, it cannot change the clamping voltage of 0.7V, so it cannot control the conduction of the transistor Q2, and therefore cannot control the conduction of the switch tube Q1, thereby protecting the circuit.

[0022] Working state 2: After the system is powered on, the load resistor R9 is in a normal working state, and the entire circuit is in a normal open state through PWR_ON. When the load resistor R9 is short-circuited due to some circumstances, the voltage of the node LOADER will quickly drop to 0V, and the node connected by the resistor R10 and the resistor R6 will be clamped to about 0.7V through the diode D1. The transistor Q2 will be quickly turned off, and the switch tube Q1 will also be quickly turned off. This will provide protection. When the load is released from the short-circuit state, the electronic switch circuit automatically returns to normal working state.

[0023] Based on the above embodiments, those skilled in the art can easily understand that the utility model also provides an electric power assist, including the above-mentioned low-cost and reliable electronic switch protection circuit.

[0024] The above is only a preferred embodiment of the utility model. It should be pointed out that for ordinary technicians in this technical field, other parts not specifically described belong to the prior art or common knowledge. Under the premise of not departing from the principle of the utility model, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the utility model.

Claims

1. A low-cost and reliable electronic switch protection circuit, characterized in that: It includes a resistor R10 with one end connected to the processor, the other end of the resistor R10 is respectively connected to the positive electrode of the diode D1 and one end of the resistor R6, the other end of the resistor R6 is connected to the base of the transistor Q2, the emitter of the transistor Q2 is grounded, and its collector is connected to one end of the current limiting resistor, the other end of the current limiting resistor is connected to one end of the resistor R1 and the control end of the switch tube Q1, the input end of the switch tube Q1 and the other end of the resistor R1 are both connected to the positive power supply VDD, and the output end of the switch tube Q1 is respectively connected to the negative electrode of the diode D1 and the load.

2. A low-cost and reliable electronic switch protection circuit according to claim 1, characterized in that: The current limiting resistor includes a resistor R2 and a resistor R3 connected in parallel.

3. A low-cost and reliable electronic switch protection circuit according to claim 1, characterized in that: The output end of the switch tube Q1 is also connected to a voltage divider feedback circuit, which includes a resistor R4 with one end connected to the output end of the switch tube Q1, the other end of the resistor R4 is respectively connected to one end of a resistor R5 and a resistor R7, the other end of the resistor R5 is used to connect to a processor, and the other end of the resistor R7 is grounded.

4. A low-cost and reliable electronic switch protection circuit according to claim 3, characterized in that: The resistor R7 is also connected in parallel with a capacitor C1.

5. A low-cost and reliable electronic switch protection circuit according to claim 1, characterized in that: The other end of the resistor R6 is also connected to one end of a resistor R8, and the other end of the resistor R8 is grounded.

6. A low-cost and reliable electronic switch protection circuit according to claim 1, characterized in that: The switch tube Q1 includes a triode and a MOS tube.

7. An electric power-assisted vehicle, characterized in that: The invention comprises a low-cost and reliable electronic switch protection circuit as described in any one of claims 1 to 6.

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