[ invention ]
The invention aims to solve the problems in the prior art, and provides an LED steering auxiliary lighting lamp control circuit which can realize automatic switching of a steering auxiliary lighting lamp.
In order to achieve the above purpose, the invention provides an LED steering auxiliary lighting lamp control circuit, which comprises a direct current power supply circuit, a trigger circuit, a delay control circuit and an LED constant current control circuit, wherein the direct current power supply circuit supplies power for a direct current power supply of the whole controller; the trigger circuit is provided with a MOS tube M1, the delay control circuit is provided with a timer U1 and an optocoupler U2, and the trigger circuit controls the on-off of the MOS tube M1 through a voltage signal of the turn signal lamp and gives a trigger signal to a second pin of the timer U1 in the delay control circuit; the delay control circuit controls the output of the optocoupler U2 to be conducted and continuously set delay time according to a trigger signal of the trigger circuit; the LED constant current control circuit is provided with a constant current control chip U3, and the output of an optocoupler U2 of the delay control circuit is used for controlling a power supply pin 8 of the constant current control chip U3 in the LED constant current control circuit.
Preferably, the trigger circuit further includes a voltage signal input terminal Ctrl of the steering lamp, a fifth resistor R5, an eighth resistor R8 and a first zener diode Z1, the trigger circuit is triggered by the voltage signal of the steering lamp, the voltage signal of the steering lamp is introduced through the input terminal Ctrl, and is connected in parallel with the eighth resistor R8, the cathode of the first zener diode Z1 and the gate of the MOS transistor M1 after being connected in series through the fifth resistor R5.
Preferably, the negative electrode of the optocoupler U2 is grounded, and the emitter is connected to the power supply pin 8 of the constant current control chip U3.
The invention has the beneficial effects that: the invention changes the protection of the control circuit into four parts: the automatic switching of the steering auxiliary lighting lamp is realized by utilizing the triggering control of the steering lamp, and the automatic switching device has the characteristics of universality, low cost, easiness in modification and addition.
The features and advantages of the present invention will be described in detail by way of example with reference to the accompanying drawings.
[ detailed description ] of the invention
Referring to fig. 1, the control circuit of the LED steering auxiliary lighting lamp comprises a direct current power supply circuit 1, a trigger circuit 2, a delay control circuit 3 and an LED constant current control circuit 4, wherein the direct current power supply circuit 1 supplies power for a direct current power supply of the whole controller; the trigger circuit 2 is provided with a MOS tube M1, the delay control circuit 3 is provided with a timer U1 and an optocoupler U2, the trigger circuit 2 controls the on-off of the MOS tube M1 through a voltage signal of the turn signal, and gives a trigger signal to a second pin of the timer U1 in the delay control circuit 3, so that false triggering can be effectively prevented, and the triggering is ensured to be reliable; the delay control circuit 3 controls the output of the optical coupler U2 to be conducted and to continuously set delay time according to the trigger signal of the trigger circuit 2, and the delay time is optimized to be suitable for the time period from turning off of the steering lamp to turning completion; the LED constant current control circuit 4 is provided with a constant current control chip U3, and the output of the optocoupler U2 of the delay control circuit 3 is used for controlling the power supply pin 8 of the constant current control chip U3 in the LED constant current control circuit 4, so that the design can effectively reduce the current impact of the LED steering auxiliary lighting lamp in the moment of on-off operation. In this embodiment, the timer U1 adopts ICM7555, the optocoupler U2 adopts PC357, the constant current control chip U3 adopts LN2516SRA, and the MOS tube M1 adopts AO3400.
Further, the trigger circuit 2 further includes a voltage signal input terminal Ctrl of the steering lamp, a fifth resistor R5, an eighth resistor R8, and a first zener diode Z1, the trigger circuit 2 is triggered by the voltage signal of the steering lamp, the voltage signal of the steering lamp is introduced through the input terminal Ctrl, and is connected in parallel with the eighth resistor R8, the cathode of the first zener diode Z1, and the gate of the MOS transistor M1 after being connected in series through the fifth resistor R5
Further, the negative electrode of the optocoupler U2 is grounded, and the emitter is connected to the power supply pin 8 of the constant current control chip U3.
Further, the dc power supply circuit 1 includes a first diode D1, a first capacitor C1, and a second capacitor C2, where after the first capacitor C1 is connected in parallel with the second capacitor C2, one end of the first capacitor C1 is grounded, and the other end of the first capacitor C is connected in series with the first diode and then connected to the positive voltage input terminal, and in this embodiment, the first diode D1 adopts SS510.
Further, the delay control circuit 3 further includes a thermistor RT1, a first resistor R1, a fourth resistor R4, a second zener diode Z2, a fourth capacitor C4, a fifth capacitor C5, and a tile capacitor CT1; one end of the first resistor R1 is connected with the positive voltage output end, the other end of the first resistor R1 is connected with the fifth capacitor C5 in series and then grounded, and the second zener diode Z2 is connected with the fifth capacitor C5 in parallel; one end of the thermistor RT1 is connected in series with the ceramic chip capacitor CT1 and then grounded, and the other end of the thermistor RT1 is connected between the first resistor R1 and the third resistor R3; the first pin of the timer U1 is grounded, the second pin is connected between the third resistor R3 and the drain electrode of the MOS tube M1, the third pin is connected with the fourth resistor R4 in series and then is connected with the positive electrode of the optocoupler U2, the fourth pin and the eighth pin are connected between the first resistor R1 and the third resistor R3, the fifth pin and the fourth capacitor C4 are connected in series and then are grounded, and the sixth pin and the seventh pin are connected between the ceramic chip capacitor CT1 and the thermistor RT 1.
Further, the LED constant current control circuit 4 further includes a second resistor R2, a sixth resistor R6, a seventh resistor R7, a third capacitor C3, a second diode D2, and an inductor L1, where in this embodiment, the second diode D2 employs SS510; one end of the second resistor R2 is connected with the positive voltage output end, the other end of the second resistor R2 is connected with the third capacitor C3 in series and then grounded, and the collector electrode of the optocoupler U2 is connected between the second resistor R2 and the third capacitor C3; after the sixth resistor R6 and the seventh resistor R7 are connected in parallel, one end is grounded, the other end is connected with the pin 1 and the pin 2 of the constant current control chip U3, after the pin 0 and the second diode D2 of the constant current control chip U3 are connected in series, a positive voltage output end is connected, the pin 3 and the pin 4 of the constant current control chip U3 are grounded, the pin 5, the pin 6 and the pin 7 of the constant current control chip U3 are connected between the pin 0 and the positive electrode of the second diode D2, one end of the inductor L1 is connected with the pin 0 of the constant current control chip U3, and the other end is connected with a negative voltage output end.
The working principle of the invention is as follows:
in the invention, the direct current power supply circuit 1 provides direct current power supply for the whole controller. The trigger circuit 2 controls the on-off of the MOS tube M1 through the voltage signal of the turn signal to give a trigger signal to the delay control circuit 3, and the design can effectively prevent false triggering and ensure reliable triggering. The delay control circuit 3 controls the output of the optocoupler U2 to be conducted according to the trigger signal of the trigger circuit 2 and continuously sets the delay time, and the delay time is optimized to be suitable for the time period from turning off of the steering lamp to turning completion. The LED steering auxiliary lighting lamp can be reliably turned on to trigger when the steering lamp flickers, and the LED steering auxiliary lighting lamp can be turned off after the steering lamp is turned off for a certain time, so that reliable and effective steering auxiliary lighting is provided; the output of the delay control circuit optocoupler U2 is used for controlling the power supply pin 8 of the constant current control chip U3 in the LED constant current control circuit, and the design can effectively reduce current impact at the moment of on-off when the LED steering auxiliary illuminating lamp works.
The above embodiments are illustrative of the present invention, and not limiting, and any simple modifications of the present invention fall within the scope of the present invention.