Texas Instruments TPS56921 Synchronous Step-Down Converter Evaluation Module TPS56921EVM-188 TPS56921EVM-188 Datenbogen
Produktcode
TPS56921EVM-188
ENFALLING
STOP
ENFALLING
p
h
R1× V
R2 =
V
- V
+R1(I +I )
ENFALLING
START
STOP
ENRISING
ENFALLING
p
h
ENRISING
V
V
- V
V
R1=
V
I 1-
+I
V
æ
ö
ç
÷
è
ø
æ
ö
ç
÷
è
ø
Tss(ms) Iss(μA)
C5(nF)=
Vref(V)
´
Test Setup and Results
1.3.2
Slow-Start Time
The slow-start time can be adjusted by changing the value of C5. Use
to calculate the required
value of C5 for a desired slow-start time
(2)
The EVM is set for a slow-start time of 5.7 ms using C5 = 0.01 µF.
1.3.3
Adjustable UVLO
The undervoltage lockout (UVLO) can be adjusted externally using R1 and R2. The EVM is set to use the
internal UVLO and R1 and R2 are not populated. Use
internal UVLO and R1 and R2 are not populated. Use
and
to calculate required
resistor values for different start and stop voltages.
(3)
(4)
1.3.4
Input Voltage Rails
The EVM is designed to accommodate different input voltage levels for the power stage and control logic.
During normal operation, the PVIN and VIN inputs are connected using a jumper across JP1. The single
input voltage is supplied at J2. If desired, these two input voltage rails may be separated by removing the
jumper across JP1. Two input voltages must then be provided at both J1 and J2.
During normal operation, the PVIN and VIN inputs are connected using a jumper across JP1. The single
input voltage is supplied at J2. If desired, these two input voltage rails may be separated by removing the
jumper across JP1. Two input voltages must then be provided at both J1 and J2.
2
Test Setup and Results
This section describes how to properly connect, set up, and use the TPS56921EVM-188 evaluation
module. The section also includes test results typical for the evaluation module and covers efficiency,
output voltage regulation, load transients, loop response, output ripple, input ripple, and start-up.
module. The section also includes test results typical for the evaluation module and covers efficiency,
output voltage regulation, load transients, loop response, output ripple, input ripple, and start-up.
2.1
Input/Output Connections
The TPS56921EVM-188 is provided with input/output connectors and test points as shown in
. A
power supply capable of supplying 4 A must be connected to J2 through a pair of 20-AWG wires. The
jumper across JP1 must be in place. See
jumper across JP1 must be in place. See
for split-input voltage rail operation. The load must
be connected to J4 through a pair of 20-AWG wires. The maximum load current capability must be 9 A.
Wire lengths must be minimized to reduce losses in the wires. Test-point TP3 provides a place to monitor
the V
Wire lengths must be minimized to reduce losses in the wires. Test-point TP3 provides a place to monitor
the V
IN
input voltages with TP4 providing a convenient ground reference. TP9 is used to monitor the output
voltage with TP10 as the ground reference.
4
TPS56921EVM-188, 9-A, SWIFT™ Regulator Evaluation Module
SLVU793 – October 2012
Copyright © 2012, Texas Instruments Incorporated