Large-current switch state detection circuit
By designing a state detection circuit for high-current switches, using resistors and controllable switches to generate VAD signals, the problem of poor motor start-up caused by the inability to detect the state of high-current switches in the prior art is solved, and safety is improved, and damage or damage caused by excessive current is prevented.
Patent Information
- Application Number
- CN202421692974.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-17
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-07-17
AI Technical Summary
Existing high-current switches cannot detect the switch status, resulting in poor motor starting and may damage the motor or injure the operator due to excessive current.
A high-current switch state detection circuit is designed. Through the cooperation of resistor R40 and resistor R44, a VAD signal is generated to detect the opening and closing state of the high-current switch by using a controllable switch and the MOS tube Q5.
The detection of the high-current switch state is achieved, which avoids the problem of poor motor start-up and prevents the risk of damage to the motor or injuring the operator due to excessive current.
Smart Images
Figure CN222994617U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of detection, and specifically relates to a large-current switch state detection circuit. Background Art
[0002] At present, large-current switches on the market do not detect the switch state, and completely rely on the on / off of the power supply to control the operation and stop of the motor. This will make it impossible to realize the braking function and the downwind starting function of the motor, resulting in poor starting of the motor. Moreover, when the situation of pressing the large-current switch first and then powering on occurs, it may cause too large current to damage the motor or even harm the operator. Summary of the Utility Model
[0003] The technical problem to be solved by the utility model is to provide a large-current switch state detection circuit. By using this detection circuit, the poor starting of the motor can be avoided, and the situation that the current is too large to damage the motor or even harm the operator will not occur.
[0004] To solve the above problems, the following technical solutions are provided:
[0005] The large-current switch state detection circuit of the utility model is characterized by including a resistor R40 and a resistor R44. One end of the resistor R40 is used to be connected to the front end of the large-current switch, the other end of the resistor R40 is connected to one end of the resistor R44, and the other end of the resistor R44 is grounded. One end of the resistor R40 connected to the resistor R44 is used to be connected to a control chip to input a VAD signal to the control chip. A controllable switch is connected in parallel at both ends of the resistor R44, and the internal resistance of the controllable switch is less than the resistance value of the resistor R44, so that after the controllable switch is closed, the resistor R44 is short-circuited. The control end of the controllable switch is adaptively connected to the rear end of the large-current switch. When the large-current switch is closed, the controllable switch is closed, and the resistor R44 is short-circuited and the VAD signal is at a low level.
[0006] Among them, one end of the resistor R40 connected to the resistor R44 is connected to one end of a resistor R41, the other end of the resistor R41 is connected to one end of a capacitor C19, the other end of the capacitor C19 is grounded, and the VAD signal is generated at one end of the resistor R41 connected to the capacitor C19.
[0007] A capacitor C20 is connected in parallel at both ends of the resistor R44.
[0008] The controllable switch contains a MOS transistor Q5. The drain of the MOS transistor Q5 is connected to the non-ground end of the resistor R44, and the source of the MOS transistor Q5 is connected to the ground end of the resistor R44. The gate of the MOS transistor Q5 is respectively connected to one end of a resistor R42 and one end of a resistor R45. The other end of the resistor R42 is used to be connected to the rear end of the large-current switch, and the other end of the resistor R45 is grounded.
[0009] A capacitor C21 is connected in parallel across both ends of the resistor R45.
[0010] Adopting the above solution has the following advantages:
[0011] Since one end of the resistor R40 in the large-current switch state detection circuit of the present utility model is used to connect to the front end of the large-current switch, the other end of the resistor R40 is connected to one end of the resistor R44, the other end of the resistor R44 is grounded, and the end of the resistor R40 connected to the resistor R44 is used to connect to the control chip to input the VAD signal to the control chip. A controllable switch is connected in parallel across both ends of the resistor R44, and the internal resistance of the controllable switch is smaller than the resistance value of the resistor R44. When in use, when the large-current switch is in the off state, the controllable switch is off and the VAD signal is at a high level; when the large-current switch is in the on state, the controllable switch is on, the resistor R44 is short-circuited, the lower end of the resistor R40 is directly grounded, and the VAD signal is at a low level, thereby realizing the detection of the large-current switch state. By detecting the large-current switch state, it can be judged whether the motor is powered on, so that the braking function and the downwind start function of the motor can be controlled, avoiding poor starting of the motor. Moreover, by detecting the large-current switch state, the situation of pressing the large-current switch first and then powering on can be avoided, so that the situation of excessive current damaging the motor or even injuring the operator will not occur. Description of the Drawings
[0012] Figure 1 is a schematic structural diagram of the large-current switch state detection circuit of the present utility model. Detailed Embodiments
[0013] The present utility model will be further described in detail below with reference to the drawings.
[0014] As Figure 1 shown, the large-current switch state detection circuit of the present utility model includes a resistor R40 and a resistor R44. One end of the resistor R40 is connected to the front end of the large-current switch, the other end of the resistor R40 is connected to one end of the resistor R44, and the other end of the resistor R44 is grounded. The end of the resistor R40 connected to the resistor R44 is connected to the control chip. The end of the resistor R40 connected to the resistor R44 is connected to one end of the resistor R41, the other end of the resistor R41 is connected to one end of the capacitor C19, the other end of the capacitor C19 is grounded, and the end of the resistor R41 connected to the capacitor C19 generates the VAD signal. The voltage at the front end of the large-current switch is the power supply voltage. In this embodiment, the power supply is a battery pack, that is, DC18V. DC18V is sampled and divided by the resistor R40 and the resistor R44 to form the VAD signal and input it into the control chip.
[0015] As Figure 1As shown in the figure, a controllable switch is connected in parallel across both ends of resistor R44. The internal resistance of the controllable switch is less than the resistance value of resistor R44, so that after the controllable switch is closed, resistor R44 is short-circuited. The control end of the controllable switch is adaptively connected to the rear end of the high-current switch. When the high-current switch is closed, the controllable switch is closed and resistor R44 is short-circuited, and the VAD signal is at a low level. The controllable switch includes MOS transistor Q5. The drain of MOS transistor Q5 is connected to the non-ground end of resistor R44, and the source of MOS transistor Q5 is connected to the ground end of resistor R44. The gate of MOS transistor Q5 is connected to one end of resistor R42 and one end of resistor R45 respectively. The other end of resistor R42 is used to be connected to the rear end of the high-current switch, and the other end of resistor R45 is grounded. In this embodiment, MOS transistor Q5 is an N-channel MOS transistor. When the high-current switch is open, the voltage at the rear end of the high-current switch is zero, the gate of MOS transistor Q5 is at a low level, and MOS transistor Q5 is not conducting
[0016]
[0017] The voltage signal of VAD is at a high level, and the control chip detects that the high-current switch is in the open state; when the high-current switch is closed, the voltage at the rear end of the high-current switch is the power supply voltage, i.e., DC18V
[0018] The gate of MOS transistor Q5 is at a high level, MOS transistor Q5 is conducting, and resistor R44 is short-circuited by the circuit
[0019] VAD = 0
[0020] The voltage signal of VAD is at a low level, and the control chip detects that the high-current switch is in the closed state.
[0021] In this embodiment, a capacitor C20 is connected in parallel across both ends of resistor R44. A capacitor C21 is connected in parallel across both ends of resistor R45.
[0022] During use, the upper end of resistor R40 is connected to the front end of the high-current switch and simultaneously to the positive pole of the battery pack. The upper end of resistor R42 is connected to the rear end of the high-current switch. The rear end of resistor R41 is connected to the ADC detection port of the control chip.
[0023] When the high-current switch is not pressed, the voltage signal of VAD is at a high level (the voltage division calculation formula through R44 and R40 is ). When the high-current switch is pressed, the voltage signal of VAD is at a low level (when the switch is turned on, DC18 and DC are connected, and the gate voltage of MOS transistor Q5 is The gate voltage of MOS transistor Q5 is at a high level. When Q5 conducts, the left end of resistor R41 is at a low level, and thus the voltage of VAD is also at a low level. By means of the two states of high and low levels of VAD, the on-off state of the high-current switch is judged, realizing the detection of the high-current switch state, and thus it can be judged whether the motor is powered on, so that the braking function and the downwind start function of the motor can be controlled, avoiding poor starting of the motor. Moreover, by detecting the high-current switch state, the situation of first pressing the high-current switch and then powering on can be avoided, so that the situation of excessive current damaging the motor or even hurting the operator will not occur.
Claims
1. A high current switch state detection circuit, characterized in that: It includes a resistor R40 and a resistor R44; one end of the resistor R40 is used to be connected to the front end of the high current switch, the other end of the resistor R40 is connected to one end of the resistor R44, and the other end of the resistor R44 is grounded; the end of the resistor R40 connected to the resistor R44 is used to be connected to the control chip to input a VAD signal to the control chip; a controllable switch is connected in parallel at both ends of the resistor R44, and the internal resistance of the controllable switch is less than the resistance value of the resistor R44, so that after the controllable switch is closed, the resistor R44 is short-circuited; the control end of the controllable switch is adaptively connected to the back end of the high current switch, when the high current switch is closed, the controllable switch is closed, the resistor R44 is short-circuited, and the VAD signal is low.
2. The high current switch state detection circuit according to claim 1, characterized in that: One end of the resistor R40 connected to the resistor R44 is connected to one end of the resistor R41, the other end of the resistor R41 is connected to one end of the capacitor C19, the other end of the capacitor C19 is grounded, and one end of the resistor R41 connected to the capacitor C19 generates the VAD signal.
3. The high current switch state detection circuit according to claim 1, characterized in that: The two ends of the resistor R44 are connected in parallel with a capacitor C20.
4. The high current switch state detection circuit according to claim 1, characterized in that: The controllable switch includes a MOS transistor Q5, the drain of the MOS transistor Q5 is connected to the non-grounded end of the resistor R44, and the source of the MOS transistor Q5 is connected to the grounded end of the resistor R44; the gate of the MOS transistor Q5 is respectively connected to one end of the resistor R42 and one end of the resistor R45, the other end of the resistor R42 is used to be connected to the rear end of the large current switch, and the other end of the resistor R45 is grounded.
5. The high current switch state detection circuit according to claim 4, characterized in that: The two ends of the resistor R45 are connected in parallel with a capacitor C21.