M51995AP/AFP
Function Description
Type M51995AP and M51995AFP are especially designed for off-line primary PWM control IC of switching mode
power supply (SMPS) to get DC voltage from AC power supply.
Using this IC, smart SMPS can be realized with reasonable cost and compact size as the number of external electric
parts can be reduced and also parts can be replaced by reasonable one.
In the following circuit diagram, MOS FET is used for output transistor, however bipolar transistor can be used with no
problem.
Start-up Circuit Section
The start-up current is such low current level as typical 90 µA, as shown in figure 1, when the VCC voltage is increased
from low level to start-up voltage VCC(START)
.
In this voltage range, only a few parts in this IC, which has the function to make the output voltage low level, is alive
and ICC current is used to keep output low level. The large voltage difference between VCC(START) and VCC(STOP) makes
start-up easy, because it takes rather long duration from VCC(START) to VCC(STOP)
.
ICCO
≈ 14 mA
ICCL
≈ 90 µA
VCC
(STOP)
≈ 9.9 V
VCC
(START)
≈ 16.2 V
Supply Voltage VCC (V)
Figure 1 Circuit Current vs. Supply Voltage
REJ03D0835-0300 Rev.3.00 Jun 06, 2008
Page 16 of 40
RENESAS [ RENESAS TECHNOLOGY CORP ]
