Texas Instruments UCD3138 Digital Power Factor Correction Pre-regulator Evaluation Module UCD3138PFCEVM-026 UCD3138PFCEVM-026 Datenbogen
Produktcode
UCD3138PFCEVM-026
Digital PFC Description
12.4.1
Background Loop
The firmware starts from function main(). In this function, after the system initialization, it goes to an infinite
loop. All the non-time critical tasks are put in this loop, it includes:
loop. All the non-time critical tasks are put in this loop, it includes:
•
Calculate voltage feed forward.
•
Clear current offset at zero load.
•
System monitoring.
•
PMBus communication.
•
Primary and secondary UART communication.
NOTE:
User can always add any non-time critical functions in this loop.
12.4.2
Voltage Loop Configuration
The voltage control loop is a pure firmware loop. V
OUT
is sensed by a 12-bit ADC, and compared with
voltage reference. The error goes into a firmware Proportional-Integral (PI) controller, and its output is
used to do current loop reference calculations.
used to do current loop reference calculations.
12.4.3
Current Loop Configuration
Current loop consists of several modules:
•
Front End (FE) Module, to configure the AFE block gain.
–
For single phase PFC, AFE0 is used.
•
Filter Module, to configure the current loop compensation.
–
FILTER1 is used.
•
DPWM Module, to generate the PWM signal driving PFC.
–
For single phase PFC, DPWM1B is used.
NOTE:
Loop Mux Module, to configure interconnection among front end, filter and DPWM modules.
12.4.4
Interrupts
There are two interrupts, the Standard Interrupt (IRQ), and the Fast Interrupt (FIQ).
•
IRQ contains the state machine and most of the PFC control firmware.
•
FIQ is used in relation to implementing OVP protections.
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Digitally Controlled Single-Phase PFC Pre-Regulator
SLUU885B – March 2012 – Revised July 2012
Copyright © 2012, Texas Instruments Incorporated