HA16108FP HITACHI [Hitachi Semiconductor], HA16108FP Datasheet - Page 19

• Manufacturer Part Number: HA16108FP
• Description: PWM Switching Regulator for High-performance Voltage Mode Control
• Manufacturer: HITACHI [Hitachi Semiconductor]

Application Note
If the IC power supply consists of an activation resistance and backup coil, as in an AC/DC converter, The
V
IN
Case:
When DC power is applied directly as the power supply of the HA16107/HA16108, without using the
transformer backup coil.
Phenomenon:
The IC may not be activated in the case of a circuit in which V
such as that shown in figure 2.
Reason:
Because of the IC circuit configuration, the timer latch block operates first.
Remedy (counter measure):
Take remedial action such as configuring a time constant circuit as shown in figure 3, to keep the V
rise speed below 10 V/100 s.
rise speed is usually around 1 V/100 s, and there is no risk of this phenomenon occurring.
Figure 2 Example of Circuit with Fast V
Input
V
18 V
V
Input
IN
IN
Time constant
1 F C
Figure 3 Sample Remedial Circuit
circuit
GND
GND
HA16107
Series
HA16107
Series
V
V
R 51
IN
IN
HA16107P/FP, HA16108P/FP
IN
rises quickly (10 V/100 s or faster),
IN
Feedback
Feedback
Rise Time
Output
Output
IN
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