MR750 MR751 MR752 MR754 MR756 MR758 MR760

4

Rectifier Device Data

Figure 9. Rectification Efficiency

Figure 10. Reverse Recovery Time

REPETITION FREQUENCY (kHz)

2.0

1.0

100

50

30

20

70

3.0

5.0

100

70

7.0 10

20

30

50

TJ = 25°C

CURRENT INPUT WAVEFORM

IR/IF, RATIO OF REVERSE TO FORWARD CURRENT

0.2

0.1

20

7.0

5.0

2.0

1.0

7.0

0.3

0.5

10

3.0

10

0.7 1.0

2.0

3.0

5.0

TJ = 25°C

IF = 5 A

3 A

1 A

IF

0

IR

trr

Figure 11. Junction Capacitance

Figure 12. Forward Recovery Time

VR, REVERSE VOLTAGE (VOLTS)

1.0

3.0

500

300

200

100

70

50

2.0

10

20

100

7.0

5.0

50

30

TJ = 25°C

1.0

IF, FORWARD PULSE CURRENT (AMP)

0.7

0.5

0.3

0.2

0.1

2.0

5.0

3.0

1.0

7.0

10

ufr = 1.0 V

TJ = 25°C

ufr

uf

tfr

TJ = 175°C

30

700

1000

30

20

10

70

ufr = 2.0 V

RS

RL

VO

Figure 13. Single–Phase Half–Wave

Rectifier Circuit

The rectification efficiency factor

σ shown in Figure 9 was

calculated using the formula:

σ +

+

R

L

.100%

+

.100%

(1)

For a sine wave input Vm sin (wt) to the diode, assumed

lossless, the maximum theoretical efficiency factor becomes:

σ

.100% + 4

.100%

+ 40.6%

(2)

For a square wave input of amplitude Vm, the efficiency

factor becomes:

σ

.100% + 50%

(3)

(A full wave circuit has twice these efficiencies)

As the frequency of the input signal is increased, the re-

verse recovery time of the diode (Figure 10) becomes signifi-

cant, resulting in an increasing ac voltage component across

RL which is opposite in polarity to the forward current, there-

by reducing the value of the efficiency factor

σ, as shown on

Figure 9.

It should be emphasized that Figure 9 shows waveform ef-

ficiency only; it does not provide a measure of diode losses.

Data was obtained by measuring the ac component of Vo

with a true rms ac voltmeter and the dc component with a dc

voltmeter. The data was used in Equation 1 to obtain points

for Figure 9.