UCD3138 digital power controller example explanation

UCD3138 isthe latest generation of digital power controller launched by Texas Instruments , which was officially released in the first quarter of 2012. Compared with the previous generation of digital power controller UCD30xx, it has important improvements in many aspects, richer functions and more powerful performance. This article is based on a switching power supply using a hard-switching full-bridge (full-wave rectification on the secondary side) topology , and introduces in detail the hardware design, software configuration and measured data of the cycle by cycle limitation function of UCD3138  . While completing the understanding of the above functions, you can also clearly understandthe advantages of UCD3138 .

UCD3138

1. Comprehensive interpretation of UCD3138 digital power controller

Abstract: UCD3138 is a fully programmable solution that gives users full control over their applications and many capabilities to differentiate their solutions. At the same time, TI is committed to simplifying our users' development work by providing best-in-class development tools, including application firmware, Code Composer Studio software development environment, and TI's power development GUI, which enables users to configure and monitor key system parameters.

2. Single Frame and Feedforward Function Description of UCD3138 Digital Power Controller

Abstract: Single Frame is a new method to detect the input voltage of the primary side on the secondary side. This method can detect the current input voltage directly and quickly on the secondary side to achieve undervoltage protection, so there is no need for additional input undervoltage protection circuits and optocouplers or digital isolators. Before the power system is officially running, the UCD3138 chip will periodically send out a single or several drive pulses to make the hard-switched full bridge work for a single or multiple cycles. At this time, a voltage can be generated at the center tap of the secondary side of the transformer. This voltage is linearly related to the input voltage. Therefore, the input voltage can be obtained by detecting the voltage at this point through UCD3138 and calculating it through software.

3. UCD3138 digital power controller cycle-by-cycle protection function description

Abstract: Each DPWM module inside the UCD3138 chip has only one cycle by cycle (CBC) hardware module. When the CBC module receives a trigger signal (FAULT), the CBC module will immediately respond to limit the duty cycle of the current DPWM A and DPWM B, thus realizing the cycle by cycle protection function.