LRC LR34063D Dc-dc converter control circuit Datasheet

LESHAN RADIO COMPANY, LTD.
DC-DC Converter
Control Circuits
LR34063
DESCRIPTION:
The LR34063 Series is a monolithic control circuit containing
the primary functions required for DC-to-DC converters.These
devices consist of an internal temperature compensated reference,comparator, controlled duty cycle oscillator with an active
current limit circuit, driver and high current output switch.This
series was specifically designed to be incorporated in Step-Down
and Step-Up and Voltage-Inverting applications with a minimum
number of external components.
DIP-8
SOP-8
FEATURE::
z Operation from 3.0 V to 40 V Input
z Low Standby Current
z Current Limiting
z Output Switch Current to 1.5 A
z Output Voltage Adjustable
z Frequency Operation to 100 kHz
z Precision 2% Reference
ORDERING INFORMATION
Device
1
Ipk
Sense
Q1
R
7
Switch
Collector
Q2
S Q
100
LR34063
DIP-8
LR34063D
SOP-8
PIN CONNECTIONS
BLOCK DIAGRAM
Drive 8
Collector
Package
2
Switch
Emitter
Switch
Collector
1
8
Driver
Collector
Switch
Emitter
2
7
Ipk Sense
Timing
Capacitor
3
6
VCC
Gnd
4
5
Comparator
Inverting
Input
Ipk
Oscillator CT
6
VCC
3
Comparator
+
–
(Top View)
Timing
Capacitor
1.25 V
Reference
Regulator
Comparator 5
Inverting
Input
4
Gnd
(Bottom View)
LR34063-1/12
LESHAN RADIO COMPANY, LTD.
LR34063
MAXIMUM RATINGS
Rating
Power Supply Voltage
Comparator Input Voltage Range
Symbol
Value
Unit
VCC
40
Vdc
VIR
– 0.3 to + 40
Vdc
Switch Collector Voltage
VC(switch)
40
Vdc
Switch Emitter Voltage (VPin 1 = 40 V)
VE(switch)
40
Vdc
Switch Collector to Emitter Voltage
VCE(switch)
40
Vdc
Driver Collector Voltage
VC(driver)
40
Vdc
Driver Collector Current (Note 1)
IC(driver)
100
mA
Switch Current
ISW
1.5
A
Power Dissipation and Thermal Characteristics
DIP-8 Package,
TA = 25°C
Thermal Resistance
SOP-8 Package, D Suffix
TA = 25°C
Thermal Resistance
PD
RθJA
1.25
100
W
°C/W
PD
RθJA
TJ
625
160
mW
°C/W
+150
°C
0 to +70
°C
Operating Junction Temperature
Operating Ambient Temperature Range
TA
Storage Temperature Range
Tstg
°C
– 65 to +150
NOTES: 1. Maximum package power dissipation limits must be observed.
ELECTRICAL CHARACTERISTICS (VCC = 5.0 V, TA = Tlow to Thigh [Note 2], unless otherwise specified.)
Characteristics
Symbol
Min
Typ
Max
Unit
Frequency (VPin 5 = 0 V, CT = 1.0 nF, TA = 25°C)
fosc
24
33
42
kHz
Charge Current (VCC = 5.0 V to 40 V, TA = 25°C)
Ichg
24
35
42
µA
OSCILLATOR
Idischg
140
220
260
µA
Discharge to Charge Current Ratio (Pin 7 to VCC, TA = 25°C)
Idischg/Ichg
5.2
6.5
7.5
–
Current Limit Sense Voltage (Ichg = Idischg, TA = 25°C)
Vipk(sense)
250
300
350
mV
Saturation Voltage, Darlington Connection (Note 4)
( ISW = 1.0 A, Pins 1, 8 connected)
VCE(sat)
–
1.0
1.3
V
Saturation Voltage, Darlington Connection
(ISW = 1.0 A, RPin 8 = 82 Ω to VCC, Forced β
VCE(sat)
–
0.45
0.7
V
hFE
50
75
–
–
IC(off)
–
0.01
100
µA
Discharge Current (VCC = 5.0 V to 40 V, TA = 25°C)
OUTPUT SWITCH (Note 3)
] 20)
DC Current Gain (ISW = 1.0 A, VCE = 5.0 V, TA = 25°C)
Collector Off–State Current (VCE = 40 V)
NOTES: 2. Tlow = 0°C ,Thigh = +70°C
3. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible.
4. If the output switch is driven into hard saturation (non–Darlington configuration) at low switch currents (≤ 300 mA) and high driver currents (≥ 30 mA),
it may take up to 2.0 µs for it to come out of saturation. This condition will shorten the off time at frequencies ≥ 30 kHz, and is magnified at high
temperatures. This condition does not occur with a Darlington configuration, since the output switch cannot saturate. If a non–Darlington
configuration is used, the following output drive condition is recommended:
IC output
Forced b of output switch :
10
IC driver – 7.0 mA *
*The 100 Ω resistor in the emitter of the driver device requires about 7.0 mA before the output switch conducts.
w
LR34063-2/12
LESHAN RADIO COMPANY, LTD.
LR34063
ELECTRICAL CHARACTERISTICS (continued) (VCC = 5.0 V, TA = Tlow to Thigh [Note 2], unless otherwise specified.)
Characteristics
Symbol
Min
Typ
Max
1.23
1.21
1.25
–
1.27
1.29
Unit
COMPARATOR
Threshold Voltage
TA = 25°C
TA = Tlow to Thigh
Vth
Threshold Voltage Line Regulation (VCC = 3.0 V to 40 V)
Input Bias Current (Vin = 0 V)
V
Regline
–
1.4
5.0
mV
IIB
–
– 20
– 400
nA
ICC
–
–
4.0
mA
TOTAL DEVICE
Supply Current (VCC = 5.0 V to 40 V, CT = 1.0 nF, Pin 7 = VCC,
VPin 5 > Vth, Pin 2 = Gnd, remaining pins open)
NOTES: 2. Tlow = 0°C , Thigh = +70°C
3. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible.
4. If the output switch is driven into hard saturation (non–Darlington configuration) at low switch currents (≤ 300 mA) and high driver currents (≥ 30 mA),
it may take up to 2.0 µs for it to come out of saturation. This condition will shorten the off time at frequencies ≥ 30 kHz, and is magnified at high
temperatures. This condition does not occur with a Darlington configuration, since the output switch cannot saturate. If a non–Darlington
configuration is used, the following output drive condition is recommended:
IC output
Forced b of output switch :
10
IC driver – 7.0 mA *
*The 100 Ω resistor in the emitter of the driver device requires about 7.0 mA before the output switch conducts.
w
LR34063-3/12
LESHAN RADIO COMPANY, LTD.
LR34063
Figure 2. Timing Capacitor Waveform
1000
VCC = 5.0 V
Pin 7 = VCC
Pin 5 = Gnd
TA = 25°C
200
100
50
ton
20
10
5.0
toff
2.0
200 mV/DIV
500
V OSC , OSCILLATOR VOLTAGE (V)
t on–off , OUTPUT SWITCH ON-OFF TIME ( µs)
Figure 1. Output Switch On–Off Time versus
Oscillator Timing Capacitor
1.0
0.01 0.02
0.05 0.1 0.2
0.5 1.0 2.0
CT, OSCILLATOR TIMING CAPACITOR (nF)
5.0 10
10 µs/DIV
Figure 4. Common Emitter Configuration Output
Switch Saturation Voltage versus
Collector Current
Figure 3. Emitter Follower Configuration Output
Saturation Voltage versus Emitter Current
VCE(sat), SATURATION VOLTAGE (V)
VCE(sat), SATURATION VOLTAGE (V)
1.8
1.7
1.6
1.5
1.4
1.3
VCC = 5.0 V
Pins 1, 7, 8 = VCC
Pins 3, 5 = Gnd
TA = 25°C
(See Note 4)
1.2
1.1
1.0
0
0.2
0.4
0.6
0.8
1.0
1.2
IE, EMITTER CURRENT (A)
1.4
1.1
1.0
0.9
Darlington Connection
0.8
0.7
0.6
VCC = 5.0 V
Pin 7 = VCC
Pins 2, 3, 5 = Gnd
TA = 25°C
(See Note 5)
0.5
0.4
0.3
0.2
0
Figure 5. Current Limit Sense Voltage
versus Temperature
0.2
0.4
0.6
0.8
1.0
1.2
IC, COLLECTOR CURRENT(A)
1.4
1.6
Figure 6. Standby Supply Current versus
Supply Voltage
3.6
400
380
3.2
VCC = 5.0 V
Ichg = Idischg
360
340
320
300
280
260
240
220
200
–55
NOTE:
Forced β = 20
0.1
0
1.6
I CC , SUPPLY CURRENT (mA)
V IPK(sense), CURRENT LIMIT SENSE VOLTAGE (V)
Pins 1, 5, 8 = Open
CT = 1.0 nF
TA = 25°C
VCC = 5.0 V
Pin 7 = VCC
Pin 2 = Gnd
2.8
2.4
2.0
1.6
1.2
CT = 1.0 nF
Pin 7 = VCC
Pin 2 = Gnd
0.8
0.4
0
–25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
0
5.0
10
15
20
25
30
VCC, SUPPLY VOLTAGE (V)
35
40
5. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible.
LR34063-4/12
LESHAN RADIO COMPANY, LTD.
LR34063
170 mH
L
1
8
180
S Q
Q2
R
Q1
7
2
1N5819
Ipk
Rsc
0.22
Vin
12 V
OSC
6
+
CT
3
CT
VCC
100
+
−
Comp.
5
1.25 V
Ref
Reg
1500
pF
4
1.0 mH
R2
R1
Vout
28 V/175 mA
47 k
2.2 k
Vout
+
330
+
CO
100
Optional Filter
Test
Conditions
Results
Line Regulation
Vin = 8.0 V to 16 V, IO = 175 mA
30 mV = ±0.05%
Load Regulation
Vin = 12 V, IO = 75 mA to 175 mA
10 mV = ±0.017%
Output Ripple
Vin = 12 V, IO = 175 mA
400 mVpp
Efficiency
Vin = 12 V, IO = 175 mA
87.7%
Output Ripple With Optional Filter
Vin = 12 V, IO = 175 mA
40 mVpp
Figure 7. Step−Up Converter
LR34063-5/12
LESHAN RADIO COMPANY, LTD.
LR34063
8
1
7
R
Vout
8
7
2
Rsc
Vin
1
Vout
2
Rsc
Vin
6
6
R ³ 0 for
constant Vin
Figure 8. External Current Boost Connections for IC Peak Greater than 1.5 A
8a. External NPN Switch
8b. External NPN Saturated Switch
(See Note 6)
6. If the output switch is driven into hard saturation (non−Darlington configuration) at low switch currents (≤ 300 mA) and high driver currents
(≥ 30 mA), it may take up to 2.0 ms to come out of saturation. This condition will shorten the off time at frequencies ≥ 30 kHz, and is magnified
at high temperatures. This condition does not occur with a Darlington configuration, since the output switch cannot saturate. If a
non−Darlington configuration is used, the following output drive condition is recommended.
LR34063-6/12
LESHAN RADIO COMPANY, LTD.
LR34063
1
8
S Q
Q2
Q1
R
7
2
Ipk
Rsc
0.33
Vin
25 V
OSC
6
100
+
CT
VCC
+
−
1.25 V
Ref
Reg
Comp.
5
1N5819
3
L
CT
220 mH
470
pF
4
3.6 k
R1
1.0 mH
Vout
5.0 V/500 mA
R2
+
1.2 k
470
+
CO
Vout
100
Optional Filter
Test
Conditions
Results
Line Regulation
Vin = 15 V to 25 V, IO = 500 mA
12 mV = ±0.12%
Load Regulation
Vin = 25 V, IO = 50 mA to 500 mA
3.0 mV = ±0.03%
Output Ripple
Vin = 25 V, IO = 500 mA
120 mVpp
Short Circuit Current
Vin = 25 V, RL = 0.1 W
1.1 A
Efficiency
Vin = 25 V, IO = 500 mA
83.7%
Output Ripple With Optional Filter
Vin = 25 V, IO = 500 mA
40 mVpp
Figure 9. Step−Down Converter
8
1
1
V
8
7
Vout
Rsc
Vin
7
2
6
2
Rsc
Vin
6
Figure 10. External Current Boost Connections for IC Peak Greater than 1.5 A
10a. External NPN Switch
10b. External PNP Saturated Switch
LR34063-7/12
LESHAN RADIO COMPANY, LTD.
LR34063
1
8
S Q
Q2
R
Q1
7
2
Ipk
Rsc
0.24
OSC
6
Vin
4.5 V to 6.0 V
88 mH
L
CT
VCC
3
+
100
+
−
Comp.
+
1.25 V
Ref
Reg
5
1500
pF
1N5819
4
1.0 mH
R1
Vout
−12 V/100 mA
953
R2
1000 mf
8.2 k
+
Vout
CO
+
100
Optional Filter
Test
Conditions
Results
Line Regulation
Vin = 4.5 V to 6.0 V, IO = 100 mA
3.0 mV = ± 0.012%
Load Regulation
Vin = 5.0 V, IO = 10 mA to 100 mA
0.022 V = ± 0.09%
Output Ripple
Vin = 5.0 V, IO = 100 mA
500 mVpp
Short Circuit Current
Vin = 5.0 V, RL = 0.1 W
910 mA
Efficiency
Vin = 5.0 V, IO = 100 mA
62.2%
Output Ripple With Optional Filter
Vin = 5.0 V, IO = 100 mA
70 mVpp
Figure 11. Voltage Inverting Converter
8
1
1
Vout
8
7
2
7
Vout
Vin
6
Vin
2
6
Figure 12. External Current Boost Connections for IC Peak Greater than 1.5 A
12a. External NPN Switch
12b. External PNP Saturated Switch
LR34063-8/12
LESHAN RADIO COMPANY, LTD.
LR34063
5.45′′
2.500′′
(Top view, copper foil as seen through the board from the component side)
LR34063
LR34063
LR34063
(Top View, Component Side)
*Optional Filter.
Figure 13. Printed Circuit Board and Component Layout
(Circuits of Figures 7, 9, 11)
INDUCTOR DATA
Converter
Inductance (mH)
Turns/Wire
Step−Up
170
38 Turns of #22 AWG
Step−Down
220
48 Turns of #22 AWG
Voltage−Inverting
88
28 Turns of #22 AWG
All inductors are wound on Magnetics Inc. 55117 toroidal core.
LR34063-9/12
LESHAN RADIO COMPANY, LTD.
LR34063
Calculation
Step−Up
V out ) V
ton/toff
V
F
* V
in(min)
* V sat
in(min)
(ton + toff)
V
Step−Down
Voltage−Inverting
V out ) V
|V out| ) V
F
* V sat * V out
in(min)
1
f
in
F
* V sat
1
f
t on ) t
toff
V
1
f
t on ) t
off
ton
) 1
t
off
t on ) t
off
ton
) 1
t
off
off
ton
) 1
t
off
ton
(ton + toff) − toff
(ton + toff) − toff
(ton + toff) − toff
CT
4.0 x 10−5 ton
4.0 x 10−5 ton
4.0 x 10−5 ton
Ipk(switch)
2I
Rsc
L(min)
CO
ǒ
out(max)
ǒ
Ǔ
t on
) 1
t
off
2I
0.3/Ipk(switch)
(V
Ǔ
* V sat)
in(min)
I
pk(switch)
9
ǒ
(V
t
on(max)
0.3/Ipk(switch)
in(min)
I
I
I outt on
V
ripple(pp)
2I
out(max)
* V sat * V out)
pk(switch)
Ǔ
t
(t
) t )
pk(switch) on
off
8V
ripple(pp)
on(max)
ǒ
out(max)
ǒ
Ǔ
t on
) 1
t
off
0.3/Ipk(switch)
(V
* V sat)
in(min)
I
pk(switch)
9
Ǔ
t
on(max)
I outt on
V
ripple(pp)
Vsat = Saturation voltage of the output switch.
VF = Forward voltage drop of the output rectifier.
The following power supply characteristics must be chosen:
ǒ
Ǔ
Vin − Nominal input voltage.
Vout − Desired output voltage, |V out| + 1.25 1 ) R2
R1
Iout − Desired output current.
fmin − Minimum desired output switching frequency at the selected values of Vin and IO.
Vripple(pp) − Desired peak−to−peak output ripple voltage. In practice, the calculated capacitor value will need to be increased due to its
equivalent series resistance and board layout. The ripple voltage should be kept to a low value since it will directly affect the
line and load regulation.
Figure 14. Design Formula Table
LR34063-10/12
LESHAN RADIO COMPANY, LTD.
LR34063
Mechanical Dimensions
Unit: mm
f
e
f
f
e
f
f
SOP-8
e
e
'
f
f
¶
'
e
fe
5
5
f
e
fe
LR34063-11/12
LESHAN RADIO COMPANY, LTD.
LR34063
Mechanical Dimensions (Continued)
DIP-8
Unit: mm
f
e
f
e
e
e
f
f
e
¶hf
f
0$;
5
f
0,1
LR34063-12/12
Similar pages