MR750 Datasheet, PDF (5/7 Pages) Motorola, Inc – HIGH CURRENT LEAD MOUNTED SILICON RECTIFIERS 50-1000 VOLTS DIFFUSED JUNCTION

MR750 SERIES
100
70
50
T_J = 175°C
CURRENT INPUT WAVEFORM
30
T_J = 25°C
20
1.0
1000
700
500
300
200
100
70
50
30
20
10
1.0
2.0 3.0 5.0 7.0 10
20 30 50 70 100
REPETITION FREQUENCY (kHz)
Figure 9. Rectification Efficiency
T_J = 25°C
2.0 3.0 5.0 7.0 10
20 30 50 70 100
V_R, REVERSE VOLTAGE (VOLTS)
Figure 11. Junction Capacitance
30
20
T_J = 25°C
10
7.0
I_F = 5 A
5.0
3A
1A
3.0
2.0
0
I_R
1.0
0.1 0.2
I_F
t_rr
0.3 0.5 0.7 1.0
2.0 3.0 5.0 7.0 10
I_R/I_F, RATIO OF REVERSE TO FORWARD CURRENT
Figure 10. Reverse Recovery Time
1.0
u_f
0.7
t_fr
u_fr
0.5
0.3
T_J = 25°C
u_fr = 1.0 V
0.2
u_fr = 2.0 V
0.1
1.0
2.0
3.0
5.0
7.0
10
I_F, FORWARD PULSE CURRENT (AMP)
Figure 12. Forward Recovery Time
R_S
R_L
V_O
Figure 13. Single−Phase Half−Wave
Rectifier Circuit
The rectification efficiency factor σ shown in Figure 9
was calculated using the formula:
σ
+
P_(dc)
P_(rms)
+
V²o^(dc)
R_L
V²o^(rms)
.100% ₊
V²o^(dc)
V²o^(ac) ) V²o^(dc)
(1)
.100%
R_L
For a sine wave input V_m sin (wt) to the diode, assumed
lossless, the maximum theoretical efficiency factor becomes:
V^2m
σ_(sine)
+
p²R_L
V^2m
.100%
+
4
π²
.100%
+
40.6%
(2)
4R_L
For a square wave input of amplitude V_m, the efficiency
factor becomes:
V^2m
σ_(square)
+
2_RL
V^2m
.100%
+
50%
(3)
R_L
(A full wave circuit has twice these efficiencies)
As the frequency of the input signal is increased, the
reverse recovery time of the diode (Figure 10) becomes
significant, resulting in an increasing AC voltage
component across R_L which is opposite in polarity to the
forward current, thereby reducing the value of the efficiency
factor σ, as shown on Figure 9.
It should be emphasized that Figure 9 shows waveform
efficiency only; it does not provide a measure of diode
losses. Data was obtained by measuring the AC component
of V_o 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.
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