STR-A6351 SanKen, STR-A6351 Datasheet - Page 13

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

Latch circuit keeps the oscillator output low and stops the power supply circuit operation when either the
The holding current of the latch circuit is 70uA MAX(Ta=25 o C) when the Vin is 20V. However, considering
In order to prevent malfunction caused by noises, etc., the delay time is set by a timer circuit incorporated in
The Vin terminal voltage, however, will drop even after the
When the Vin terminal voltage falls to the shutdown
When the Vin terminal voltage reaches the operation start
Consequently, the latch circuit operation prevents the Vin
terminal voltage from rising abnormally by managing the voltage
between 10.1V(TYP) and 17.6V(TYP). The Fig.10 shows the voltage waveform when the latch circuit is in
STR-A6300 Application Notes
7.4 Latch Circuit
Overvoltage Protection(OVP) or Thermal Shutdown(TSD) circuit operates.
slight voltage increase at low temperature, it is required to flow 100uA or higher to the Vin terminal from the
start-up resistor in order to maintain the latch circuit operation.
the IC, and thereafter, the latch circuit starts its operation when either the OVP or TSD circuit operates for
8usec or longer.
latch circuit starts its operation because the constant voltage
power supply(Reg.) circuit in the control circuitry continues its
operation and maintains higher circuit current.
voltage(7.9V MIN) or lower, the circuit current becomes below
70uA(Ta=25 o C), and the Vin terminal voltage starts rising
again.
voltage(17.6V TYP), it falls as the circuit current increases again.
③
コントロール部
Control part
VIN
Added(Vz=6.8V)
Added
Fig.9 OCP compensation circuit with input voltage
追加
追加
Vz=6.8V
OCP/FB
②⑤
GND
D
S
図９ 入力電圧によるOCP補正回路
⑦
①
④
⑧
3
RA
680
C5
R4
I1
I3
Page 13
R5
RB
I2
Added
D
追加
P
ＲＡ＝680×
（ＴＹＰ）
（ＴＹＰ）
ID Peak(Vin MAX) :
Input Voltage MAX, Drain current at MAX load
ID Peak(Vin MIN) :
Input Voltage MIN, Drain current at MAX load
VIN(DC)MIN:入力電圧(MIN)の整流後電圧
VIN(DC) MAX : Input Volt.(MAX) after rectifying
VIN(DC) MIN : Input Volt.(MIN) after rectifying
VIN(DC)MAX:入力電圧(MAX)の整流後電圧
IDpeak(VinMAX)：
入力電圧MAX、最大負荷時のドレイン電流
IDpeak(VinMIN)：
入力電圧MIN、最大負荷時のドレイン電流
ＲＢ＝
17.6V
10.1V
Ｖ
ＩＮ
VIN(DC)MIN-(6.8+0.76)
Fig.10 Example of Vin waveform at
Latch Circuit ON
図10 ラッチ回路動作時Ｖ 端子波形例
IDpeak(VinMIN)-IDpeak(VinMAX)
RA×(6.8+0.76)
VIN(DC)MAX-VIN(DC)MIN
IDpeak(VinMIN)
０．７６
Added
（Ver.1.2）
ＩＮ
Time
時間