KA3511DS Fairchild Semiconductor, KA3511DS Datasheet - Page 15

• Manufacturer Part Number: KA3511DS
• Description: IC PWM/SECONDARY COMBO 22-DIP
• Manufacturer: Fairchild Semiconductor

Specifications of KA3511DS

• Pwm Type: Current Mode
• Number Of Outputs: 3
• Frequency - Max: 10kHz
• Duty Cycle: 50%
• Voltage - Supply: 14 V ~ 30 V
• Buck: No
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: -25°C ~ 85°C
• Package / Case: 22-DIP (0.400", 10.16mm)
• Frequency-max: 10kHz
• Topology: Push-Pull
• Output Voltage: 40 V
• Output Current: 200 mA
• Switching Frequency: 10 KHz
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 25 C
• Fall Time: 50 ns
• Mounting Style: Through Hole
• Rise Time: 100 ns
• Synchronous Pin: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6.8 R/S FLIP FLOP (LATCH) BLOCK
There is a R-S F/F (Latch) circuit for shutdown operation in the KA3511. R-S F/F (Latch) is con-
trolled by OVP, UVP, and some delayed remote ON/OFF signal.
If any output of OVP or UVP is High, SET signal of R-S F/F is high status and it produces PWM
“High” and main power is turned off. When remote signal is high, its delayed output signal is sup-
plied to RESET port of R-S F/F and it produces SET low. So output Q is low status. At this time,
PWM maintains high status by delayed remote high signal.
After main power is turned-off by OVP/UVP and initialized by remote, if remote signal is changed to
low, main power becomes operational.
When you test KA3511, Remote ON/OFF signal should be toggled once for initializing.
OVP+
High
High
Low
Low
High
SET
Low
Low
Low
Figure 10. R-S F/F Block Diagram
RESET
High
High
Low
Low
15
Qn+1
High
High
Low
Qn
Rev C, November 1999
Qn+1
High
High
Low
Qn