A Guide to Other Documentation for all Members of UCD3138 Family of Products
32
SNIU028A – February 2016 – Revised April 2016
Copyright © 2016, Texas Instruments Incorporated
Introduction
The output of the compensator is passed to a Digital PWM (DPWM) generator. The DPWM has two
outputs, which can be used in many different ways. There are modes for synchronous rectification,
multiple phases, various bridge topologies, and LLC configurations. In addition to the 2 DPWM outputs,
the DPWM has other signals which are used externally and internally. These include:
•
Frame start – start of a switching cycle
•
Sample Trigger – signals Front end to take a sample
•
Sync out – signals another DPWM to start a frame
•
Sync in – a signal to this DPWM to start a frame
•
Fault signals – signal the DPWM to take various fault actions
These signals will be covered in much more detail in
.
The peripherals can be run tied together as shown above, or they can be used in different groupings and
interconnections, not shown in the picture above. For example, the DPWM can be used to trigger the Error
ADC, which will trigger the Filter at the end of its conversion.
The UCD3138 device supports multiple sets of the Digital Power Peripherals affording the ability to control
upto 3 feedback loops (voltage or current) and drive 8 outputs simultaneously. To inter-connect all the
DPPs, there is a large module called the Loop Mux. This permits a high degree of flexibility in DPP
configuration. Any Front End can be connected to any Filter, and any Filter output can be connected to
any DPWM. Additionally, information can be passed between the peripherals. For example, the output of
one Filter (eg. controlling a slow Voltage loop), can contribute to the reference of another Front End (eg.
monitoring a fast current loop) and enable implementation of nested loops (such as in Average Current
mode control).
In addition, the DPPs in UCD3138 provide other modules and functions for power supply and control.
These include:
•
Fault Handling
•
Cycle by Cycle Current Limit
•
Constant Power/Constant Current
•
Ramp up/Ramp Down
•
Peak Current Mode control
and so on.
There is also a module called Fault Mux which connects fault detection circuitry outputs to control inputs,
primarily on the DPWMs, to customize fault handling and recovery.
This documentation provides information about the DPP modules in UCD3138, starting with a detailed
description, continuing with some configuration examples, and ending with a reference section which lists
each bit field in each DPP module.