Use an LDO and PLD for Power-Supply Enable and Disable Functions (Download)
Many systems require enabling and disabling through control lines or when applying the input power. While a small microcontroller (MCU) can implement the enable/disable function, you still need to write, maintain, and flash code for it. Many designs using a system-on-chip (SoC) have an MCU within that chip; adding another is redundant. Moreover, the MCU in the SoC isn’t low power enough to both remain always on and provide the enable controller function.
This article discusses a low-cost, low-power enable controller hardware solution that consumes only microamperes of current using a low-dropout linear regulator (LDO) plus a programmable logic device (PLD). The PLD comes preprogrammed with the logic you need to implement the decision-making function of the enable controller.
