Texas Instruments TPS25944X635EVM, User Manual

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General Configurations
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4.4 Test Procedures
Use the following procedures for testing:
1. The operational voltage range of the two rails VIN1 and VIN2 can be adjusted by changing a few
resistor settings, as listed in Table 5 .
Table 5. Operational Range Setting for VIN1, VIN2 = 12 V, 5 V and 3.3 V
VIN Operational Range Rail: VIN1 or VIN2 R9 R13 R11 R22 R8
12 V: 10.5 V to 16 V VIN1 16.9 k Ω 32.4 k Ω 47 k Ω
(Default)
5 V: 4.6 V to 5.7 V VIN1 23.2 k Ω 105 k Ω 137 k Ω
3.3 V: 3 V to 3.8 V VIN1 48.7 k Ω 187 k Ω 237 k Ω
2.3 V to 15.5 V (Default) VIN2 No PoP 32.4 k Ω
5 V: 4.6 V to 5.7 V VIN2 130 k Ω 100 k Ω
3.3 V: 3 V to 3.8 V VIN2 237 k Ω 169 k Ω
2. Turn on the power supply and set the power supply voltage to 12 V on CH1 and CH2.
3. Turn off the power supply. Hook up CH1 and CH2 of the PWR635 assembly as shown in Figure 3 .
4. Ensure that the output load is disabled and the power supply is set properly for the DUT. Connect the
negative probe of DMM to TP12 or TP25 (GND) to the test points in Table 6 .
5. Turn on the power supply. Verify that the voltages shown in Table 6 are obtained. Use only one power
supply at a time for this verification.
Table 6. PWR635 DMM Readings at Different Test Points
Voltage Test on Measured Voltage Voltage Tested Measured Voltage
(CH1) Reading on (CH2) Reading
VIN1 (TP3) 12 ±0.3 VDC VIN2 (TP15) 12 ±0.3 VDC
EN_UV1 (TP8) 1.13 ±0.1 VDC EN_UV2 (TP17) 12 ±0.3 VDC
OVP1 (TP5) 0.742 ±0.1 VDC OVP2 (TP18) 0.742 ±0.1 VDC
IMON1 (TP11) 33.8 mV ±5 mVDC IMON2 (TP22) 33.8 mV ±5 mVDC
VOUT1 (TP2) 12 ±0.3 VDC VOUT2 (TP16) 12 ±0.3 VDC
PG1 (TP9) 2.40 ±0.1 VDC PG2 (TP21) 2.4 ±0.1 VDC
FLTb1 (TP4) 10.51 ±0.5 VDC FLTb2 (TP20) 10.5 ±0.5 VDC
4.4.1 Preliminary Test
Use the steps in the following sections for preliminary testing.
4.4.1.1 For CH1 (J3-J2)
1. With the power supply set to 12 V on CH1, verify that the red LED (D2) is off. Press the EVM RST
switch (S1) and verify that the voltage at VOUT1 (TP2) starts falling slowly below 12 V and that the
FLTb1 red LED (D2) turns ON. Release S1.
2. Reduce the input voltage on VIN1 and monitor VOUT1. Verify that VOUT1 (TP2) starts falling and is
fully turned off when VIN1 (TP3) reaches 9.5 V (±0.5 V). Verify that the FLTb1 red LED (D2) turns ON.
3. Increase the input voltage on VIN1 and monitor VOUT1. Verify that VOUT1(TP2) starts increasing and
is fully turned off when VIN1 (TP3) reaches 16.5 V (±1 V). Verify that the FLTb1 red LED (D2) turns
ON.
4.4.1.2 For CH2 (J8-J7)
1. With the power supply set to 12 V on VIN2, press the EVM RST switch (S2) and verify that the voltage
at VOUT2 (TP16) starts falling slowly below 12 V and that the green PG LED (D7) turns off and the
RED FLTb2 LED (D6) turns on. Release S2.
2. Reduce the input voltage on VIN2 and monitor VOUT2. Verify that VOUT2 (TP16) starts falling and is
8 TPS25944X635EVM: Evaluation Module for TPS25944X SLUUBC2A – May 2015 – Revised July 2015
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