Datasheet

Fusion Power Peripheral
AD
_
03
AD
_
07
DPWM1
PI
(
Gv
)
+
+
-
-
UCD3138
Vref
Vb
Ev
Iin
CLA1
(
Gc
)
Calculate
Vrms
Calculate
1/Vrms
2
Iref
A
B
c
Ui
Vrms
Conditioning
&
Rectification
Km
FE0
DPWM1B
Vbus_sen
Vin_N
I
_
shunt
EAP0
UART
Interface
Vin_L
AD
_
08
Cycle by cycle limit
Vbus_ov
COMP
_
F
OVP
PMBus
Interface
Single-phase PFC
Configuration
COMP
_
D
I_CT1
www.ti.com Digital PFC Description
12.2 UCD3138 Pin Definition
In this EVM, the PFC DC bus voltage feedback loop control is implemented using firmware execution by
the ARM7 microcontroller, while the high-speed current loop control is implemented in the digital power
peripherals in the UCD3138. The DC bus voltage, AC line and AC neutral voltages are sensed using the
general purpose ADC in the ARM block. This is executed while the current signal is sensed and
processed using the Front-End (EADC) block in the digital power peripherals. All protection functions such
as cycle-by-cycle current limiting and overvoltage protection are implemented using the high-speed analog
comparators available in the UCD3138.
12.2.1 UCD3138 Pin Definition in Single-Phase PFC
UCD3138 is a 64-pin device. When using the UCD3138 as a single-phase PFC controller, the pins used
are defined in Figure 28.
Figure 28. Definition of UCD3138 in Single-Phase PFC Control
27
SLUU885B–March 2012–Revised July 2012 Digitally Controlled Single-Phase PFC Pre-Regulator
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