ZHCS688I November 2011 – March 2018 TPS65217
PRODUCTION DATA.
The TPS65217x device has a predefined power-up–power-down sequence which, in a typical application, does not require changing. However, users can define custom sequences through I2C control. The power-up sequence is defined by strobes and delay times. Each output rail is assigned to a strobe to determine the order in which the rails are enabled. The delay times from one strobe to the next are programmable in a range from 1 ms to 10 ms.
NOTE
Although the user can modify the power-up and power-down sequence through the SEQx registers, those registers are reset to default values when the device goes to the SLEEP, OFF, or RESET state. In practice, this situation means that the power-up sequence is fixed and a custom power-down sequence must be written each time the device is powered up.
Custom power-up and power-down sequences can be tested and verified in the ACTIVE state (PWR_EN pin pulled high) by using I2C to toggle the SEQUP and SEQDWN bits. Permanent changes to the default power-up sequence timing require custom programming at the TI factory.