The TPS7H3014 has three input power
supplies:
- IN, the input supply to
provide power to the TPS7H3014 IC. It is recommended to decouple this power
supply with at least 1μF as close to the pin as possible. In this
application, VIN = 12V.
- PULL_UP1, which is the input
supply to program the output voltage high (VOH) of all the enable
outputs (ENx). These outputs are connected to the regulator enable inputs to
control the sequence up and down. It is recommended to decouple this power
supply with at least 1μF as close to the pin as possible. In this
application, the VPULL_UP1 = 3.3V. This is a typical voltage used
in electronic systems and satisfies the logic inputs of most regulators in
the market.
- PULL_UP2, which is the input
supply to program the output voltage high (VOH) of PWRGD and
SEQ_DONE outputs. These outputs are typically connected to the system
controller (typically an FPGA or ASIC) and/or to the house-keeping
controller. In daisy chain configurations, SEQ_DONE is connected to UP of
subsequent TPS7H3014 I.C. as shown in Figure 8-15. It is recommended to decouple this power supply with at
least 1μF as close to the pin as possible. In this application, the
VPULL_UP1 = 3.3V. This is a typical voltage of controller
I/Os.
The TPS7H3014 also has two regulated
voltage outputs that need to be decoupled for good electrical and radiation
performance. These are:
- REFCAP, the 1.2V reference, used
internally in the device to generate all ratiometric voltage reference such as:
- VTH_SENSEx
- IHYS_SENSEx
- VTH_UP
- VTH_DOWN
Decouple this reference
with a 470nF ceramic capacitor as close to the pin as possible. Do not load
this pin externally.
- VLDO, this is the output of the
internal regulator used to provide power to the internal circuits on the
TPS7H3014. Is recommended to decouple this regulator with at least 1μF as close
to the pin as possible. The valid loading of this regulator is:
- To turn-off channels 2–4
as needed.
- To pull-up the
FAULT open-drain output.