Texas Instruments UCC2891 User Manual
Size:
307.97 Kb
Download

www.ti.com

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-Amaximum. Make sure VIN is initially set to 0 V and connected to J1 as shown inFigure 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 –November2003–RevisedDecember 2006

Using the UCC2891 Active Clamp Current Mode PWM Controller

9

Submit Documentation Feedback

www.ti.com

Power Up/Down Test Procedures

7 Power Up/Down Test Procedures

OVERALL EFFICIENCY vs

OUTPUT CURRENT

 

93

 

 

 

 

 

 

 

 

VIN = 48 V

 

 

 

 

 

 

91

 

 

 

 

 

 

 

89

 

 

 

 

 

 

%

 

 

 

 

VIN = 72 V

 

-

 

 

 

 

 

 

 

Efficiency

 

 

VIN = 36 V

 

 

 

87

 

 

 

 

 

 

 

 

 

 

 

 

 

Percent

85

 

 

 

 

 

 

83

 

 

 

 

 

 

 

 

 

 

 

 

 

 

81

 

 

 

 

VOUT = 3.3 V

 

 

 

 

 

 

 

 

 

 

 

 

fS = 300 kHz

 

79

 

 

 

 

 

 

 

2

6

10

14

18

22

26

 

 

 

IOUT - Output Current - A

 

Figure 3.

POWER LOSS vs

OUTPUT CURRENT

 

12

 

 

 

 

 

 

 

 

 

VOUT = 3.3 V

 

 

 

 

 

 

 

fS = 300 kHz

 

 

 

 

 

 

10

 

 

 

 

 

 

 

- W

 

 

 

 

 

 

 

 

- Power Loss

8

 

 

 

 

 

 

 

6

 

 

 

 

 

 

 

LOSS

 

VIN = 72 V

 

 

 

 

 

 

P

 

 

 

 

 

 

 

 

 

4

 

 

 

 

VIN = 48 V

 

 

 

 

 

 

 

 

 

 

 

 

 

VIN = 36 V

 

 

 

 

2

 

 

 

 

 

 

 

 

2

6

10

14

18

22

26

30

 

 

 

IOUT - Output Current - A

 

 

GAIN AND PHASE

 

 

 

vs

 

 

 

 

 

 

FREQUENCY

 

 

 

 

60

 

 

 

180

 

 

 

 

Phase

 

 

 

 

40

 

 

 

120

 

 

20

 

 

 

60

 

dB

 

Gain

 

 

- °

 

 

 

 

 

Gain -

0

 

 

 

0

Phase

 

 

 

 

 

 

-20

 

 

 

-60

 

 

 

VIN = 36 V

 

 

 

 

 

-40

IOUT = 10 A

 

 

-120

 

 

 

gM =-8dB

 

 

 

 

 

 

ΦM = 50°

 

 

 

 

 

-60

 

 

 

-180

 

 

10

100

1 k

10 k

100 k

 

 

 

 

f - Frequency - Hz

 

 

 

Figure 5.

Figure 4.

10

Using the UCC2891 Active Clamp Current Mode PWM Controller

SLUU178A –November2003–RevisedDecember 2006

Submit Documentation Feedback

www.ti.com

Power Up/Down Test Procedures

GAIN AND PHASE

Input Ripple Voltage

 

 

 

vs

 

 

 

 

 

 

FREQUENCY

 

 

VIN = 36 V

 

60

 

 

 

180

 

 

 

 

 

 

IOUT = 30 A

 

 

 

Phase

 

 

 

 

40

 

 

 

120

 

 

 

 

 

 

 

500 mV/div

 

20

 

 

 

60

1 V peak-to-peak

 

 

 

 

 

dB

 

 

 

 

 

- °

Gain-

0

 

 

 

0

Phase

 

 

 

Gain

 

 

 

 

-20

 

 

 

-60

 

 

 

VIN = 48 V

 

 

 

 

 

-40

IOUT = 10 A

 

 

-120

 

 

 

gM =-10dB

 

 

 

 

 

 

ΦM = 50°

 

 

 

 

 

-60

 

 

 

-180

 

 

10

100

1 k

10 k

100 k

 

 

 

 

f - Frequency - Hz

 

 

t − T ime − 2.5 μs/div

 

 

 

 

 

 

 

 

 

Figure 6.

 

 

Figure 8.

 

 

 

 

 

 

 

 

 

 

 

 

Output Ripple Voltage

 

 

 

GAIN AND PHASE

 

 

 

 

 

 

vs

 

 

 

 

 

 

FREQUENCY

 

 

VIN = 72 V

 

 

 

 

 

 

 

60

 

 

 

180

IOUT = 30 A

 

 

 

 

 

 

 

 

 

Phase

 

 

 

 

40

 

 

 

120

 

 

 

 

 

 

 

50 mV/div

 

 

 

 

 

 

36 mV peak-to-peak

 

20

 

 

 

60

 

dB

 

 

 

 

 

- °

Gain-

0

 

Gain

 

0

Phase

 

 

 

 

 

 

 

-20

 

 

 

-60

 

 

 

VIN = 72 V

 

 

 

 

 

-40

IOUT = 10 A

 

 

-120

 

 

 

gM =-9dB

 

 

 

 

 

 

Φ M = 50°

 

 

 

 

 

-60

 

 

 

-180

 

 

10

100

1 k

10 k

100 k

t − T ime − 2.5 μs/div

 

 

 

 

 

 

 

 

 

f - Frequency - Hz

 

 

 

Figure 9.

Figure 7.

SLUU178A –November2003–RevisedDecember 2006

Using the UCC2891 Active Clamp Current Mode PWM Controller

11

Submit Documentation Feedback

Power Up/Down Test Procedures

Output Ripple Voltage

VIN = 36 V

IOUT = 30 A

50 mV/div

23 mV peak-to-peak

t − T ime − 2.5 μs/div

Figure 10.

Transformer Primary

VIN = 48 V

IOUT = 10 A

VPRI

(40 V/div)

IPRI

(0.5 A/div)

t − T ime − 2.5 μs/div

Figure 11.

12 Using the UCC2891 Active Clamp Current Mode PWM Controller

www.ti.com

SR Gate Drive

VIN = 36 V

6.3 V, QF Gate (J5)

(5 V/div)

8.4 V, QR Gate (J6)

(5 V/div)

t − T ime − 1 μs/div

Figure 12.

SR Gate Drive

VIN = 72 V

12.3 V, QF Gate (J5)

(5 V/div)

5.4 V, QR Gate (J6)

(5 V/div)

t − T ime − 1 μs/div

Figure 13.

SLUU178A –November2003–RevisedDecember 2006

Submit Documentation Feedback