Scheme description：

The night light has three modes, shutdown, induction and steady on, which can be selected by DIP switch.

When the induction mode is selected, the function is controlled by the HS6604 chip. After power-on, REL first pulls down the duration of 2s (lights up for 2s) , then goes through the high resistance state blocking time of 3.5 s, and then enters the normal working mode:REL is a high resistance state (the lamp does not turn on) when no one is present; if human body movement is detected, REL pulls down (the lamp turns on) , timing lasts for 30s, and can trigger repeatedly; the maximum driving current of REL foot is 200mA.

The HS6604 also has a built-in charge management chip that can charge a single lithium-ion battery directly from the USB port. The charging current can be adjusted to up to 500MA without the need for MOSFET, detection resistors or isolation diodes, the charging speed is guaranteed without the danger of overheating, and the precision reaches ± 1% (± 42 mv) of 4.2 V preset charging voltage.CHRG port can indicate the charging state, when in charge cycle, the strong pull-down state is effective, the light turns on; once the charging cycle is terminated or filled, the light turns off.

There are several advantages in making charging night light scheme with HS6604：

1.Extremely low power consumption, standby current of induction state is only 20UA, and peripheral components are simple

2.External three-terminal voltage regulator can be omitted,HS6604 can directly supply voltage regulator to the probe

3.It can save the driving triode /MOS tube, and the maximum driving current of HS6604 can reach 200mA

4.The charge management chip can be dispensed with, and a single lithium-ion battery can be charged directly from the USB port through the HS6604

A chip + analog probe can realize all functions of human sensing small night light

Schematic diagram：

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