AN5765
ICs for TV
■ Technical Information (continued)
3. Operational explanation
1) Temperature protection circuit is built in.
The circuit operates at approx. 150°C (typ.) and
pin 7 output becomes low-level (0 V).
V7
6.45 V
If the temperature falls due to the output current
decrease, the protection circuit turns off and pin 7 re-
turns to the high-level again.
0 V
150°C
Tj
2) Pin 3 and pin 7 are equipped with current limiter circuit.
The limiter circuit operates at;
I3 ≤ −400 mA
V3
V7
5 V
6.45 V
I7 ≤ −1 000 mA
The current value is not guaranteed value since
the value fluctuates due to dispersion and temperature
characteristic.
0 V
0 V
−400 mA
−1 000 mA
I3
I7
3) Pin 2 (SW input) is internally biased.
Pin 2 is biased at approx. 2 V when open. Pin 2 can be biased at approx. 3 V if 22 kΩ resistor is connected
between pin 2 and pin 3 (5 V). However, take sufficient care to its absolute value fluctuation since the built-in
resistor of IC has its dispersion and temperature dependency.
IC inside
To microcomputer
5 V
3 V
3
2
22 kΩ
30 kΩ
20 kΩ
Open
4) The Reset output becomes Low (0.15 V or less) by pin 3 voltage (at V3 ≤ 4.1 V).
If VCC is turned off prior to regulator output, regulator output once becomes high (0.7 V) at a voltage of 0.7
V or less but there is no problem in terms of characteristics.
VCC (pin 1)
VCC (pin 1)
Regulator (pin 3)
Reset (pin 5)
Regulator (pin 3)
Reset (pin 5)
0.7 V
0 V
0 V
(When pin 3 turns off first)
(When VCC turns off first)
6
PANASONIC [ PANASONIC ]
