Texas Instruments UCC2891 manual Power Up/Down Test Procedures

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Power Up/Down Test Procedures

6Power Up/Down Test Procedures

The following test procedure is recommended primarily for power up and shutting down the EVM.

Whenever the EVM is running above an output load of 15 ADC, the fan should be turned on. Also, never walk away from a powered EVM for extended periods of time.

1.Working at an ESD workstation, make sure that any wrist straps, bootstraps or mats are connected referencing the user to earth ground before power is applied to the EVM. Electrostatic smock and safety glasses should also be worn.

2.Prior to connecting the DC input source, VIN, it is advisable to limit the source current from VIN to 3.5-A maximum. Make sure VIN is initially set to 0 V and connected to J1 as shown in Figure 2.

3.Connect the ammeter A1 (0A to10A range) between VIN and J1 as shown in Figure 2.

4.Connect voltmeter (can optionally use voltmeter from VIN source if available), V1 across VIN as shown in Figure 2.

5.Connect LOAD1 to J8 as shown in Figure 2. Set LOAD1 to constant current mode to sink 0 ADC before VIN is applied.

6.Connect voltmeter, V2 across J9 and J10 as shown in Figure 2.

7.Increase VIN from 0 V to 36 VDC.

8.Observe that VOUT is regulating when VIN is at 36 V.

9.Increase VIN to 48 V.

10.Increase LOAD1 from 0 A to 15 ADC.

11.Turn on fan making sure to blow air directly on the EVM.

12.Increase LOAD1 from 15 ADC to 30 ADC.

13.Decrease LOAD1 to 0 A.

14.Decrease VIN from 48 VDC to 0 V.

15.Shut down VIN.

SLUU178A –November 2003 –Revised December 2006 Using the UCC2891 Active Clamp Current Mode PWM Controller 9

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