Circuit Description
6
Circuit Description
The UCC28880EVM-616 is a non-isolated AC-to-DC high-side buck configuration with direct feedback.
The EVM, on the input side, has a half-wave rectifier assembled for rectification of AC-to-DC, followed by
an EMI filter.
The pre-set output voltage is set to ~13 V (typical) if jumper J3 is not connected, or ~5 V (typical) when
the jumper is inserted. In the high-side buck configuration the output at OUT pin of connector P2 is
positive with respect to GND.
NOTE:
The GND node is one diode drop (D2) above the input neutral (N) node.
In addition to the UCC28880 device, the EVM holds the following key components:
•
A Half-Wave Rectifier (D1, D2)
•
EMI Filter (L1, C1, C2)
•
Freewheeling Diode (D4)
•
Inductor (L2)
•
Load Capacitor (C5) and Pre-Load Resistor (R5)
•
Feedback Path (C4, D5, R2, R3, R4, J3)
•
V
AC
Input Connector (P1)
•
V
DC
Output Connector (P2)
Table 3. UCC28880EVM-616 Board Jumpers
DESIGNATOR
DESCRIPTION
NOTE
JP1
Selecting feedback resistor values to select between 5-V and 13-V output:
Output is measured from pin 2
to pin 1 of P2.
• When the jumper is inserted, the output is 5 V.
• When left open, the output is 13 V.
Table 4. UCC28880EVM-616 Test Points
DESIGNATOR
DESCRIPTION
TP1
Buck switch node
TP2
High voltage rectified DC
TP3
GND
TP4
GND
TP5
VOUT
Table 5. UCC28880EVM616 Board Connectors
CONNECTOR
PIN NUMBER
DESCRIPTION
P1
L (pin1)
AC mains terminal input (line). AC mains input can be connected in either
polarity. If DC is fed into this connector, then connect the positive V
DC
to this
node.
Warning: This is a high-voltage node.
N (pin2)
AC main terminal input (neutral). AC Mains input can be connected in either
polarity. If DC is fed into this connector, then connect negative V
DC
to this
node.
Warning: This is a high-voltage node.
P2
Out (5 V/13 V) (pin1)
Positive output node.
Gnd (pin2)
Negative output node (one diode drop above the input N).
7
SLUUB56A – July 2014 – Revised August 2014
UCC28880EVM-616 High-Side Buck Evaluation Module
Copyright © 2014, Texas Instruments Incorporated
