Power management IC composed of load management

The microprocessor implements load management by controlling the operation of the power supply, as shown in Figure 1. There are N power supplies in Figure 1, and each power supply carries a load (there are N loads). Each power supply has an enable terminal (EN, high level is valid) or a power off control terminal (SHDN, low level is valid). The I/O port of the microprocessor is connected to the EN terminal or SHDN terminal of the power supply, and outputs a logic level to control the power on or off, so that load management can be achieved. For example, a product has 6 power supplies. In a certain working state, power supplies 1 to 3 need to be turned on, so that loads 1 to 3 are powered on and work, and power supplies 4 to 6 are turned off. Loads 4 to 6 lose power and do not work. Just add a logic high level to the EN terminal of power supplies 1 to 3 and a low level to the EN terminal of power supplies 4 to 6.

Figure 2 is a functional structure diagram of a power management IC (TPS65021) from TI. It is powered by a lithium-ion battery and is interfaced with the device by a microprocessor via I2C. TPS65021 has internal control function circuits and 6 power supplies (3 DC/DC converters, 3 linear regulators LDO, output voltages V1-V6). It can power mobile phones and implement load management.

There are three kinds of power supplies in digital cameras: system power supply, LCD power supply and white light LED drive power supply (backlight and flash power supply). The system power supply part is composed of 4 DC/DC converters, as shown in Figure 3. It supplies power to the CCD camera, I/F interface circuit, CPU core and telescopic lens motor respectively. The load management can be done through the microprocessor. The microprocessor can also control the LCD backlight brightness and flash drive circuit according to the working state requirements.