MC34063A
DC/DC CONVERTER CONTROL CIRCUIT
SPEC NO: DS34063A-00
!
BLOCK DIAGRAM
SC
1
Q2
Q1
80
SE
2
7
IPK
QS
R
8
DRI
CT
3
IS
Oscillator
TC
6
Comparator
1.25V
Reference
Voltage
+
VCC
-
GND
4
5
FB
!
PIN DESCRIPTIONS
PIN 1: SC
PIN 2: SE
PIN 3: TC
- 1.6A switch collector
- Darlington switch emitter
- Oscillator timing capacitor
PIN 5: FB
- Feedback comparator inverting input
PIN 6: VCC - Power supply input
PIN 7: IPK
PIN 8: DRI
- Highside current sense input,
VCC - V
IPK
=300mV
- Drive collector
PIN 4: GND - Power GND
!
APPLICATION INFORMATION
•
DESIGN FORMULA TABLE
CALCULATION
t
ON
t
OFF
(t
ON
+ t
OFF
)
MAX
C
T
I
C (SWITCH)
RS
L(MIN)
Co
STEP-DOWN
V
OUT
+ V
F
V
IN(MIN)
- V
SAT
- V
OUT
1
F
MIN
4x10
-5
t
ON
2I
OUT(MAX)
0.33/I
C(SWITCH)
V
IN(MIN)
- V
SAT
- V
OUT
t
ON(MAX)
I
C(SWITCH)
I
C ( SWITCH)
(t
ON
+ t
OFF
)
8V
RIPPLE ( P - P )
STEP-UP
V
OUT
+ V
F
-
V
IN(MIN)
V
IN(MIN)
- V
SAT
1
F
MIN
4 x 10
-5
t
ON
2I
OUT(MAX)
(
t
ON
+ t
OFF
)
t
OFF
VOLTAGE-INVERTING
V
OUT
+ V
F
V
IN
- V
SAT
1
F
MIN
4 x 10
-5
t
ON
2I
OUT(MAX)
(
t
ON
+ t
OFF
)
t
OFF
0.33/ I
C (SWITCH)
V
IN(MIN)
- V
SAT
t
ON(MAX)
I
C(SWITCH)
I
OUT
t
ON
V
RIPPLE(P - P)
0.33/ I
C (SWITCH)
V
IN(MIN)
- V
SAT
t
ON(MAX)
I
C(SWITCH)
I
OUT
t
ON
V
RIPPLE(P - P)
ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
www.analog.com.tw
TEL: (8863)577-2500 FAX:(8863)577-2510
5
AIC [ ANALOG INTERGRATIONS CORPORATION ]
