AN8037 Panasonic Semiconductor, AN8037 Datasheet - Page 17

• Manufacturer Part Number: AN8037
• Description: AC-DC switching power supply control IC with standby mode
• Manufacturer: Panasonic Semiconductor

Voltage Regulators
[1] Operation descriptions (continued)
7. Local resonance operation (power MOSFET turn-on delay circuit) (continued)
8. Bottom-on function (AN8037 only)
Application Notes (continued)
with the high or low level in comparison to the threshold voltage on the TR pin, the AN8037 detects transformer
resetting on the falling edge across the threshold voltage.
input range for worldwide use, thus eliminating difficulty in turning on the power MOSFET when V
the minimum value. Refer to figure 12.
Not acceptable during
T
Unlike the AN8027 or our conventional AN8026, AN8028, or AN8029 IC, which detects transformer resetting
This ensures the reliable local resonance operation of the IC regardless of input voltage fluctuations in a wide
ON
and T
(AN8037 only)
0 V
0.25 V
0 V
0 V
• Bottom-on function (AN8037 only)
OFF(min)
One shot
V
A one-shot pulse is generated at the moment the signal level on the TR pin switched
to low level from high level reaches 0.25 V (typical) after the turn-on signal is received.
Refer to the next section for details.
DS
V
I
D
TR
periods.
Input voltage; Low
V
V
AN8027, AN8037
Transformer resetting
P
IN
0.25 V typ.
comparator
t
pd
V
TR
Transformer resetting
detected on falling edge.
0.7 V typ.
Figure 11
Lower limit clamp
Upper limit clamp
Figure 12
0.7 V typ.
0.15 V typ.
0 V
0.25 V
0 V
0 V
V
DS
V
TR
GND
V
CC
I
TR
D
Input voltage; High
V
V
IN
P
Upper limit clamp current
Adjust so that the
current will be 3 mA.
AN8027, AN8037
t
pd
D
R
clamp current
TR
B
Lower limit
V
TR
DS
NB
0.7 V typ.
is close to
17