How to protect circuitry

　　Author ：Iflowpower – Portable Power Station Supplier

This circuit parses use the rechargeable battery voltage test circuit made by the low power consumption amplifier LM393, which can monitor the voltage of the charging battery in real time. When the battery voltage rises to the set value, the circuit can automatically send light alarm prompt, and Encharge and protect the battery. This circuit is simple and easy to work, stable and reliable.

First, the circuit working principle circuit is as shown above. LM393 is a commonly used low-power dual op amp, which only uses one of them to block a positive voltage comparator to monitor the voltage of the rechargeable battery. The 2V voltage regulator tube is used here to supply a 2V reference voltage to the same phase input terminal of the LM393.

Adjusting the resistor R is the sampling potentiometer, the positive phase input of the LM393 2 foot through the LM393 to monitor the voltage of the charging battery. The rechargeable battery monitored by this circuit is 12.6V.

When the charging battery voltage is lower than the set voltage of the circuit, the positive phase input pin 2 of the LM393 is lower than the reference voltage (2V) of its 3 foot, at this time, the LM393 output terminal 1 foot output is low, and its LED is off , PNP triode cut-off, relay reset, battery chargeable. When the charging battery is charged to ride the voltage above the set value or more, the 2 foot voltage of the LM393 is higher than the reference voltage of its 3 foot. At this time, the output terminal output of the LM393 becomes high, and the LED lights up.

NPN triode saturation, relay work, disconnection circuit, battery stop charging. Second, the adjustable resistor R on the selection circuit board of the component is used to set the test voltage of the circuit. When making, adjusting the resistor R Optional 50K multi-ring fine-tuning resistance, the regulator tube selects 1N4615 regulated diode, its voltage regulated value is 2V, the power is 0.

5W. LED uses high brightness red LED. PNP triode can be used with S8550 and other PNP type three-pole.

Relay optional 5V single-knife double roll relay. Dual operation amplifier selects a double-line-in-one 8 foot package low power dual op amp LM393, the output of the operating voltage ranges from 2 to 36V. When there is no LM393, use LM358 or LM258 instead of.

Third, the debugging of the circuit This circuit lights up when the input voltage is 12.7V, and the relay is sucking. This circuit is used to monitor 12V rechargeable battery voltages.

When debugging, access the adjustable power supply in the battery interface, adjust to a set voltage 0. A few volts, then adjust the variable resistance R, until the LED lights up, adjust the adjustable power supply to a lower than it is set. Volt or 0.

A few volts, LEDs extinguish. The adjustable power is disconnected, and the battery can be accessed. (Single lithium-ion battery is overflowing 4.

2V, 3 string lithium-ion battery is overlying 12.6V, and the voltage after 12V battery oil is around 13.8V), then this circuit only uses 5V ~ 12V circuit, if it is more, you want to Zhang Da LED current limiting resistors, but also in the relay suction and coil string resistance.

LM358 is double op amp, this circuit only uses one, and another idle is not used. If you want, you can also use this idle unused op amp to overwrace protection or temperature protection.