SRP Hitachi Semiconductor, SRP Datasheet - Page 19

• Manufacturer Part Number: SRP
• Description: High Speed Current Mode PWM Control IC for Switching Power Supply
• Manufacturer: Hitachi Semiconductor

Figure 8 Relationship Between Triangular Wave and Maximum ON Duty of PWM Pulse
Case 1.
Setting large maximum duty cycle.
Case 2.
Setting small maximum duty cycle.
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Figure 7 Oscillation Frequency vs. Timing Resistance
500
200
100
50
20
10
5
500
PWM maximum ON pulse
PWM maximum ON pulse
1k
2k
Timing resistance R
Triangular wave
Triangular wave
5k
10k 20k
In the case of small C
(ex. C
In the case of large C
(ex. C
T
Ta = 25¡C
V
( )
IN
50k 100k 200k
T
T
= 15V
= 3300pF, R
= 0.033 F, R
Du max = 95%
fosc = 52kHz
Du max = 40%
fosc = 52kHz
T
T
T
T
= 10k )
= 680 )
and small R
and large R
T
T
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