STR-A6351 SanKen, STR-A6351 Datasheet - Page 8

• Manufacturer Part Number: STR-A6351
• Description: STR-A6300 Series
• Manufacturer: SanKen

STR-A6300 Application Notes
Drain to source
breakdown voltage
Drain leakage current
ON-Resistance
Switching time
Thermal resistance
7 FUNCTIONS OF EACH TERMINAL AND OPERATION
7.1
The start-up circuit detects the voltage at the VIN terminal (Pin 3), and
the circuit starts and stops the operation of the control IC. The power
supply circuit (VIN terminal input) of the control IC employs a circuit as
shown on Fig.1.
At start-up of the power supply, C2 is charged through the start-up
resistor Rs. The Rs value, due to the slight increase of the latch
circuit holding current (70uA MAX) at low temperature, should be
determined in order for 100uA or higher current to flow at the minimum
AC input voltage.
However, where the Rs value is too high, the current charging C2 after
AC input shall be reduced, as a result, longer time is required to reach the operation start voltage.
Consequently, Rs value as well as C2 value that will be mentioned later should be monitored.
Vin terminal voltage falls immediately after the control circuit starts its operation, but the drop ratio of the
voltage shall reduce by increasing the C2 capacitance. Consequently, even though the start-up of the drive
winding voltage is delayed, the Vin terminal voltage would not reach the operation stop voltage to maintain
the start-up operation.
However, the time of AC input to operation start becomes longer since it takes much time to charge
the C2, if the C2 capacitance is too large. In general, a power supply shall operate at the value of
C2(=4.7~10uF approx.) and of Rs (=470kohm~1Mohm) for a wide
input start-up.
As shown on Fig.2, circuit current is kept below 50uA max.
(Vin=15.0V, Ta=25℃) until the control circuit starts its operation, and
a higher value of Rs is applicable to the circuit.
The control circuit starts its operation by start-up circuit as
soon as the Vin terminal voltage reaches 17.6V(TYP.), and the current
Vin Terminal(Pin 3)/Start-up Circuit
6.3
Parameter
ELECTRICAL CHARACTERISTICS OF MOSFET(STR-A6351)
*Please refer to each data sheet for details.
8-1
8-1
8-1
8-1
-
Pin
V
I
rDS
tf
Θ
DSS
Symbol
DSS
ch- Ｆ
(ON)
Page 8
MIN
650*
-
-
-
-
Ratings
TYP
-
-
-
-
-
MAX
-
300
3.95*
250
52*
STR-A6300
50μA
(Max)
Fig.2. Vin-I
5mA
(Max)
図2 V
D
V
uA
Ohm
nsec
o C
GND
I
V
7,8
IN
IN
Unit
/W
IN
Fig.1. Start-up
3
2,5
端子電圧
Rs
図1 起動回路
10.1V
(typ)
IN(Circuit current)
See each data
sheet.
Channel to
internal frame
C2
－
回路電流
15V
Conditions
（Ver.1.2）
19.4V
(Max)
Circuit
D2
I
IN
V
IN
D
P