Texas Instruments TPS51220EVM, Руководство пользователя

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5 Configuration
Users can configure this EVM per the following configurations.
5.1 Switching Frequency Selection
The switching frequency can be set by the RF-resistor (R15) or applying external clock into RF pin on the EVM.
Default setting is 280-kHz using RF resistor.
Table 5-1. Switching Frequency Selection
Connection
Internal
Add RF-resistor from RF to GND and be R31 open
[ ]
8
sw
1 10
= [kHz]
RF
f
´
W
External
Apply external clock signal to SYNC (5 Vpp and 50% duty) , remove R15 in addition, and add
0-Ω to R31.
5.2 Skip Mode and Control Scheme Selection
The skip mode can be set by the SKIPSEL1,2 pins using JP3 and JP4 on the EVM.
Default setting is Auto-skip.
Table 5-2. Skip Mode Selection
Jumper (JP3, JP4) set to SKIPSEL1,2 Skip
Top (1-2 pin shorted) GND CCM
Second (3-4 pin shorted) VREF2 Auto-skip
Third (5-6 pin shorted) VREG3 OOA (<400-kHz)
Bottom (7-8 pin shorted) VREG5 OOA (>400-kHz)
5.3 Current-Sensing Selection
The current-sensing scheme can be set by the external current sensing devices, using some resistors on the
EVM.
Default setting is Inductor DCR sensing
Table 5-3. Current-Sensing Scheme Selection (CH1)
R8 R29 R35 R36 R6 R7 R25
Inductor DCR Put on
(1)
Put on
(1)
(if necessary)
Put on
(1)
Put on
(1)
Open Open Open
External Resistor Put on
(1)
Put on
(1)
(if necessary)
Put on
(1)
Open Put on
(1)
Cut trace
Open Open
(1) "Put on” means add appropriate resistor.
Table 5-4. Current Sensing Scheme Selection (CH2)
R18 R28 R33 R37 R20 R19 R26
Inductor DCR Put on
(1)
Put on
(1)
(if necessary)
Put on
(1)
Put on
(1)
Open Open Open
External Resistor Put on
(1)
Put on
(1)
(if necessary)
Put on
(1)
Open Put on
(1)
Cut trace
Open Open
(1) "Put on” means add appropriate resistor.
For external resistor sensing, cut the trace as follows.
www.ti.com Configuration
SLVU251B – JUNE 2008 – REVISED FEBRUARY 2022
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TPS51220 Buck Controller Evaluation Module User's Guide 5
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