Develops a mature and easy-to-use battery power supply switching circuit

Recently I have read several posts about power switching, so I will share with you the power switching circuit used in one of my projects. Thank you.
Features:
1. Supports touch switch and self-locking Switch
2. Support automatic power-on of external power supply (which can be achieved by welding d17)
3. Support for standby power output
4. The external power supply and lithium-ion power supply are automatically switched. Due to the existence of the PMOS internal Continuous Diode, no voltage drop will occur during the switching process.
5. The dual-PMOS Back-to-Back Connection prevents the external power from being poured into the lithium battery.

The schematic diagram is as follows:
1. vcc_5v0 external power input
2. li_bat lithium battery
3. vcc_sys Main Power Output
4. vcc_sb standby power supply output
Control Interface Description:
1. Press the ex_pwr_key switch button to enter the ex_pwr_key, and an external touch switch or a self-locking switch. The switch is effective at a low level.
2. The pwr_key_det button is used to detect the Switch Status of the single chip microcomputer. It is mainly applicable to the touch switch.
3. sys_pwr_hold power supply is maintained, which is effective at a high level. It is useful when you touch the switch or the system wants to control the shutdown.
Typical applications:
1. the power switch uses the touch switch to detect the pwr_key_det status and control sys_pwr_hold. This enables the system to start up, hold for XX seconds, and shut down the system.
2. The on-board Device and d17 external ACC signal can enable auto ignition, auto start, auto flameout, and automatic shutdown after xx delay.
3. Use the self-locking switch to disconnect d17 without the need for pwr_key_det and sys_pwr_hold to automatically switch the external power supply from the built-in power supply, and use the small self-locking switch to control high current On-Off.

 

Develops a mature and easy-to-use battery power supply switching circuit