www.fairchildsemi.com
KA7515
SMPS Controller
Features
• Good load regulation over a wide load for external
components.
• Internal soft-start for quiet start-up.
• Start-up supply current less than 1.6mA.
• Switch-oft supply current less than 10mA.
• Burst operation under short-circuit conditions
• Thermal shutdown through over-temperature.
Description
The KA7515 provides the necessary features to implement
switching mode power supply with a minimal external parts
count. Internally implemented circuits include 3V refer-
ence voltage block, supply voltage monitoring block to
control output through supply voltage and overload amplifier
block to control output by external road variation. The
KA7515 controls the power MOSFET and performs all
necessary regulation and monitoring function in free running
flyback converters.
8-DIP
1
Internal Block Diagram
Rev. 5.0
©2000 Fairchild Semiconductor International
KA7515
Absolute Maximum Ratings (T
A
=25°C)
°
Parameter
Supply Voltage
Collector Supply Voltage
Output current, Sink or Source
Operating Temperature
Storage Temperature
Symbol
V
CC
V
C
I
O
T
OPR
T
STG
Value
20
13
12
-25 ~ + 85
-65 ~ + 150
Unit
V
V
mA
°C
°C
Electrical Characteristics (T
A
= 25°C)
°
Parameter
Start-up Hysteresis
Start-up Current (1)
Start-up Current (2)
Start-up Current (3)
Switch On Voltage
Switch Off Voltage
Switch On Current
Switch Off Current
Voltage Limiter (Pin 2)
Voltage Limiter (Pin 3)
Control Input Voltage
Gain In Control Range
Basic Value
Maximum Peak Value
Overload Range Upper Limit
Overload Range Lower Limit
Gain In Overload Range
Input Current
In Short-Circuit Operation
Peak Value (1)
Peak Value (2)
Output Pulse Width
Output Pulse Width
Current Consumption (1)
Current Consumption (2)
Overload Point
V
2(PK)
1
V
2(PK)
2
t
W
1
t
W
2
I
6
1
I
6
2
-I
2
V
1
= 3.5V
V
1
= 0V
V
1
= 3.5V
V
1
= 0V
V
1
= 3.5V
V
1
= 0V
V
3
= V
4
, V
2
= 0V
2.8
2.35
3.5
2.5
-
-
400
3.0
2.65
5
4
12
12
660
3.4
2.95
6.5
5.5
15
15
850
V
V
µs
µs
mA
mA
µA
I
ST
1
I
ST
2
I
ST
3
V
6E
V
6A
I
6E
I
6A
V
2(MAX)
V
3(MAX)
V
I(CTRL)
G
V(CTRL)
V
2B
V
2(MAX)
V
IH
V
IL
G
V(OVER)
I
1
V
6
= 5V
V
6
= 8V
V
6
= V
6E
V
1
= V
4
= V
8
= GND
V
1
= V
4
= V
8
= GND
V
1
= V
4
= V
8
= GND
V
1
= V
4
= V
8
= GND
V
6
= 10V (IC Switch-Off)
V
6
= 10V (IC Switch-Off)
V
6
= 10V (IC Switch-On)
V
6
= 10V (IC Switch-On)
V
6
= 10V (IC Switch-On)
V
6
= 10V (IC Switch-On)
V
6
= 10V (IC Switch-On)
V
6
= 10V (IC Switch-On)
V
6
= 10V (IC Switch-On)
V
6
= 10V (IC Switch-On)
-
-
-
11
6
-
-
5.8
5.8
370
48
0.9
2.8
370
60
1
90
0.5
1.0
1.1
12
6.5
9.0
8.0
6.8
6.8
400
51
1.0
3.0
400
200
2
140
0.75
1.5
1.6
13
7
12.0
10.0
7.8
7.8
430
54
1.15
3.4
430
290
3
180
mA
mA
mA
V
V
mA
mA
V
V
mV
dB
V
V
mV
mV
dB
µA
Symbol
Conditions
Min.
Typ.
Max.
Unit
2
KA7515
Electrical Characteristics (T
A
= 25°C)
(Continued)
°
Correction Current
Positive Value
Negative Value
Threshold Value
Delay Time
Saturation Voltage (1)
Saturation Voltage (2)
Rising Edge
Falling Edge
Under VTG. Protection (1)
Over VTG. Protection
Under VTG. Protection (2)
Overtemperature
Protection
Voltage Pin 3
V
3
I
3
= 1mA
-
0.35
0.5
V
V
8(P)
V
8(N)
V
8(S)
t
D
V
SAT
1
V
SAT
2
+dV5/dt
-dV5/dt
∆V
6(UV)
V
6(MAX)
V
3(UV)
T
J
I
5
= -1.0A
I
5
= 1.0A
V
1
= 3.5V
V
1
= 3.5V
V
6MIN
= V
6a
+
∆V
6
-
-
-
I
8
= 1mA
I
8
= -1mA
-
-
0.7
0.15
40
-
-
-
4.0
50
0.3
14
0.925
150
0.75
0.22
50
0.4
2.5
2.5
50
75
0.5
15
1
175
0.8
0.25
60
0.7
3.0
3.0
-
-
1
16
1.075
200
V
V
mV
µs
V
V
V/µs
V/µs
V
V
V
°C
3
Microcontroller MCU
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