DC-DC Converter Control Circuits
MC34063A
● OUTPUT SWITCH CURRENT IN EXCESS OF
●
●
●
●
●
1.5A
2% REFERENCE ACCURACY
LOW QUIESCENT CURRENT:2.5mA(TYP.)
OPERATING FROM 3V TO 40V
REQUENCY OPERATION TO 100KHz
ACTIVE CURRENT LIMITING
8 SOP/ 8 DIP PIN Configulation
Switch
1
Collector
Switch
2
Emitter
Timing
3
Capacitor
Ground
8
7
6
Drive
Collector
Ipk Sense
Vcc
Comparator
DESCRIPTION
The MC34063A series is a monolithic control
circuit delivering the main functions for DC-DC
voltage converting.
The device contains an intermal temperature
compensated reference, comparator, duty cycle
controlled oscillator with an active current limit
circuit driver and high current output switch.
Output voltage is adjustable through two external
resistors with a 2% reference accuracy.
Employing a minimum number of external
components the MC34063A devices series is
designed for Step-Down, Step-Up and
Voltage-lnverting applications.
4
5
- Input
ORDERING INFORMATION
Device
MC34063AD
MC34063AN
Package
8 SOP
8 DIP
BLOCK DIAGRAM
Drive
Collector
8
s
R
Q
Q2
Q1
1
Switch
Collector
Ipk Sense
7
Ipk Oscillator
2
3
Switch
Emitter
Timing
Capacitor
Vcc
6
Comparator
+
-
Comparator
lnverting
input
1.25V
Reference
Regulator
4
GND
5
HTC
1
DC-DC Converter Control Circuits
ABSOLUTE MAXIMUM RATINGS
SYMBOL
V
cc
V
ir
V
SWC
V
SWE
V
CE
V
dc
I
dc
I
sw
P
tot
T
op
PARAMETER
Power Supply Voltage
Comparator input Voltage Range
Switch Collector Voltage
Switch Emitter Voltage (VSWC=40V)
Switch Collector to Emitter Voltage
Driver Collector Voltage
Driver Collector Current
Switch Current
Power Dissipation at T
amb
=25℃(for Plastic Package )
(for SOIC Package )
Operating Ambient Temperature Range
MC34063A
VALUE
50
-0.3 to 40
40
40
40
40
100
1.5
1.25
0.625
0 to 70
UNIT
V
V
V
V
V
V
㎃
A
W
℃
℃
℃
℃
T
stg
Storage Temperature Range
-40 to 150
Absolute Maximum Rating are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
THERMAL DATA
SYMBOL
PARAMETER
R
thi-amb
Thermal Resistance Junction-ambient (
*
)
( ) This Value depends from thermal design of PCB on which the device is mounted.
*
Max
DIP-8
100
SO-8
160
UNIT
℃/w
CONNECTION DIAGRAM
(top view)
SWC
SWE
TC
GND
4
5
SC11080
PIN CONNECTIONS
PIN NO
1
2
3
4
5
6
7
8
SYMBOL
SWC
SWE
TC
GND
CII
Vcc
I
PK
DRC
NAME AND FUNCTION
Switch Collector
Switch Emitter
Timing Capactor
Ground
Comparator lnverting lnput
Voltage Supply
I
PK
Sense
Voltage Driver Collector
1
8
DRC
IPK
V
CC
CII
HTC
2
DC-DC Converter Control Circuits
MC34063A
ELECTRICAL CHARACTERISTICS(
Refer to the test circuits, V
CC
=5V, T
a
=T
LOW
to T
HIGH
, unless
otherwise specified, see note 2)
OSCILLATOR
SYMBOL
F
OSC
I
chg
I
dischg
I
dischg
/I
chg
V
ipk(sense)
PARAMETER
Frequency
Charge Current
Discharge Current
Discharge to Charge Current Ratio
Current Limit Sense Voltage
TEST CONDITIONS
MIN.
o
V
pin5
= 0 V ,C
T
= 1nF ,T
a
= 25 C 24
o
24
V
CC
= 5 to 40V ,T
a
= 25 C
o
140
V
CC
= 5 to 40V ,T
a
= 25 C
o
5.2
Pin 7= V
CC
,T
a
= 25 C
o
250
I
chg
= I
dischg
,T
a
= 25 C
TYP.
33
33
200
6.2
300
MAX. UNIT
42 KHz
42
㎂
260
㎂
7.5
350 ㎷
OUTPUT SWITCH
SYMBOL
PARAMETER
V
CE(sat)
Saturation Voltage,
Darlington connection
V
CE(sat)
Saturation Voltage
h
FE
I
C(off)
DC Current Gain
Collector Off-State Current
TEST CONDITIONS
I
SW
= 1A ,Pins 1,8 connected
I
SW
= 1A ,R
pin8
= 82Ω to V
CC
,
Forced β ~ 20
I
SW
= 1A, V
CE
= 5V, T
a
= 25
o
C
V
CE
= 40V
MIN.
TYP.
1
0.45
50
120
0.01
MAX. UNIT
1.3
V
0.7
V
100
㎂
COMPARATOR
SYMBOL
PARAMETER
V
th
Threshold Voltage
Reg
line
I
IB
Threshold Voltage Line Regulation
Input Bias Current
TEST CONDITIONS
T
a
= 25
o
C
T
a
= T
LOW
to T
HIGH
V
CC
= 3 to 40V
V
IN
= 0V
MIN. TYP.
1.225 1.25
1.21
1
-5
MAX. UNIT
1.275 V
1.29
V
5
㎷
-400 ㎁
TOTAL DEVICE
SYMBOL
PARAMETER
I
CC
Supply Current
TEST CONDITIONS
MIN.
V
CC
= 5 to 40V, C
T
=1㎋
Pin7= V
CC
,V
pin5
>V
th
, Pin2=GND
Remaining pins open
for MC34063A
T
a
= 25
o
C ,C
T
=1㎌ ,Pin5= 0V
for MC34063A
TYP.
2.5
MAX. UNIT
4
㎃
V
START-UP
Start-up Voltage(note 4)
2.1
V
Notes:
1) Maximum package power dissipation limit must be observed.
2) T
LOW
= 0
o
C, T
HIGH
70
o
C
=
3) If Darlington configuration is not used, care must be taken to avoid deep saturation of output switch.
The resulting switch-off time may be adversely affected.
In a Darlington configuration the following output driver condition is suggested:
/(I
-1㎃
*
)≥10
Forced β of output current switch= I
COUTPUT CDRIVER
*
Current less due to a built in 1KΩ antileakage resistor.
4) Start-up Voltage is the minimum Power Supply Voltage at which the internal oscillator begains to work.
HTC
3
DC-DC Converter Control Circuits
TYPICAL ELECTRICAL CHARACTERISTICS
Emitter Follower Configuration Output Saturation
Voltage vs Emitter Current
V
CE
(sat)
(V)
1.75
1.70
1.65
1.60
1.55
1.50
1.45
1.40
0
400
800
1200
I
E
(㎃)
0
0.01
0.1
1
100
V
CC
=5V
Pin1,7,8=V
CC
Pins3,5=GND
T
a
=25℃
MC34063A
Output Switch ON-OFF Time vs Oscillator
Timing Capacitor
T
on
T
off
(㎲)
200
150
V
CC
=5V
Pin7=V
CC
Pin5=GND
T
a
=25℃
T
on
50
T
off
C
T
(㎋)
Common Emitter Configuration Output Switch
Saturation Voltage vs Collector Current
V
CE
(sat)
(V)
1.0
0.8
0.6
0.4
0.2
0
0
400
800
1200
1
C
(㎃)
V
CC
=5V
Pin7=V
CC
Pins2,3,5=GND
T
a
=25℃
Forced β =20
Darlington Connection
Darlington Configuration Collector Emitter
Saturation Voltage (V
CE(sat)
) vs Temperature
V
CE
(sat)
(㎷)
1000
950
900
850
800
750
-40
V
CC
=5V
I
C
=1A
0
40
80
120
T
J
(℃)
Power Collector Emitter Ssturation Voltage
(V
CE(sat)
) vs Temperature
V
CE
(sat)
(㎷)
600
V
CC
=5V
550
500
450
400
350
-40
Current Limit Sense Voltage Voltage
(V
ipk
)
vs
Temperature
V
ipk
(㎷)
320
MC34063A
310
300
290
V
CC
=5V
280
270
-40
I
C
=1A
I
chg
=
I
dischg
0
40
80
120
T
J
(℃)
0
40
80
120
T
J
(℃)
HTC
4
DC-DC Converter Control Circuits
TYPICAL ELECTRICAL CHARACTERISTICS (Continued)
Reference Voltage vs Temperature
Vref
(V)
1.265
V
CC
=5V
1.260
1.255
1.250
1.245
1.240
-40
8
6
4
2
0
-40
MC34063A
Bias Current vs Temperature
I
Bias
(㎁)
10
V
CC
=5V
C
II
to GND
0
40
80
120
T
J
(℃)
0
40
80
120
T
J
(℃)
Supply Current vs Temperature
I
CC
(㎃)
5
4
3
2
1
0
-40
V
CC
=5V
C
T
=1㎋
Supply Current vs Input Voltage
I
CC
(㎃)
4.0
3.5
3.0
2.5
2.0
1.5
T
J
= 25℃
C
T
= 1㎋
0
40
80
120
T
J
(℃)
0
10
20
30
40 V
in
(V)
HTC
5
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