UC2524 [TI]
Advanced Regulating Pulse Width Modulators; 高级稳压脉宽调制器
| 型号： | UC2524 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | Advanced Regulating Pulse Width Modulators |
| 文件： | 总8页 (文件大小：326K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
UC1524
UC2524
UC3524
Advanced Regulating Pulse Width Modulators
FEATURES
DESCRIPTION
• Complete PWM Power Control
The UC1524, UC2524 and UC3524 incorporate on a single monolithic chip
all the functions required for the construction of regulating power supplies, in-
verters or switching regulators. They can also be used as the control element
for high-power-output applications. The UC1524 family was designed for
switching regulators of either polarity, transformer-coupled dc-to-dc convert-
ers, transformerless voltage doublers and polarity converter applications em-
ploying fixed-frequency, pulse-width modulation techniques. The dual
alternating outputs allow either single-ended or push-pull applications. Each
device includes an on-chip reference, error amplifier, programmable oscilla-
tor, pulse-steering flip-flop, two uncommitted output transistors, a high-gain
comparator, and current-limiting and shut-down circuitry. The UC1524 is
characterized for operation over the full military temperature range of -55°C
to +125°C. The UC2524 and UC3524 are designed for operation from -25°C
to +85°C and 0° to +70°C, respectively.
Circuitry
• Uncommitted Outputs for
Single-ended or Push-pull
Applications
• Low Standby Current…8mA Typical
• Interchangeable with SG1524,
SG2524 and SG3524, Respectively
BLOCK DIAGRAM
V
REF
OSC OUT
3
16
+5V TO ALL
INTERNAL
CIRCUITRY
REFERENCE
REGULATOR
15
V
IN
+5V
12
C
E
A
Q
6
7
R
T
T
OSC
R
Q
11
13
C
A
(RAMP)
C
B
+5V
+5V
E A
INV INPUT
NI INPUT
1
2
COMPARATOR
14
5
E
B
GROUND
(SUBSTRATE)
8
–SENSE
+SENSE
10k
C L
1k
4
10
SHUTDOWN
9
COMPENSATION
SLUS180D - NOVEMBER 1999 - REVISED AUGUST 2002
UC1524
UC2524
UC3524
CONNECTION DIAGRAM
ABSOLUTE MAXIMUM RATINGS (Note 1)
Supply Voltage, VCC (Notes 2 and 3) . . . . . . . . . . . . . . . . . 40V
Collector Output Current. . . . . . . . . . . . . . . . . . . . . . . . . 100mA
Reference Output Current . . . . . . . . . . . . . . . . . . . . . . . . 50mA
Current Through CT Terminal . . . . . . . . . . . . . . . . . . . . . . –5mA
Power Dissipation at TA = +25°C (Note 4). . . . . . . . . . 1000mW
Power Dissipation at TC = +25°C (Note 4). . . . . . . . . . 2000mW
Operating Junction Temperature Range . . . . –55°C to +150°C
Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C
INV INPUT
1
16
15
14
13
12
11
V
REF
REF
REG
EA
V
NON INV
INPUT
IN
2
3
4
E
B
OSC OUT
C
B
CLSENSE(+)
Note 1: Over operating free-air temperature range unless oth-
erwise noted.
Note 2: All voltage values are with respect to the ground termi-
CL
C
A
CLSENSE (–-)
5
6
7
8
nal, pin 8.
E
A
Note 3: The reference regulator may be bypassed for operation
from a fixed 5V supply by connecting the VCC and ref-
erence output pins both to the supply voltage. In this
configuration the maximum supply voltage is 6V.
Note 4: Consult packaging section of databook for thermal lim-
itations and considerations of package.
R
T
S/D
10 S/D
COMP
OSC
C
T
9
GND
RECOMMENDED OPERATING CONDITIONS
Supply Voltage, VCC. . . . . . . . . . . . . . . . . . . . . . . . . . 8V to 40V
Reference Output Current . . . . . . . . . . . . . . . . . . . . . 0 to 20mA
Current through CT Terminal. . . . . . . . . . . . . –0.03mA to –2mA
Timing Resistor, RT . . . . . . . . . . . . . . . . . . . . . 1.8kΩ to 100kΩ
Timing Capacitor, CT . . . . . . . . . . . . . . . . . . . 0.001µF to 0.1µF
Operating Ambient Temperature Range
UC1524 . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C
UC2524 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –25°C to +85°C
UC3524 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = –55°C to +125°C
for the UC1524, –25°C to +85°C for the UC2524, and 0°C to +70°C for the UC3524, VIN = 20V, and f = 20kHz,
TA = TJ.
UC1524/UC2524
MIN MAX
UC3524
UNITS
PARAMETER
Reference Section
TEST CONDITIONS
MIN
MAX
Output Voltage
4.8
5.0
10
5.2
20
50
4.6
5.0
10
5.4
30
50
V
Line Regulation
VIN = 8 to 40V
mV
mV
dB
mA
%
Load Regulation
IL = 0 to 20mA
20
20
Ripple Rejection
f = 120Hz, TJ = 25°C
66
66
Short Circuit Current Limit
Temperature Stability
Long Term Stability
Oscillator Section
Maximum Frequency
Initial Accuracy
VREF = 0, TJ = 25°C
100
0.3
20
100
0.3
20
Over Operating Temperature Range
TJ = 125°C, t = 1000 Hrs.
1
1
mV
C = .001mfd, R = 2kΩ
300
5
300
5
kHz
%
T
T
R and C Constant
T
T
Voltage Stability
V
= 8 to 40V, T = 25°C
1
5
1
5
%
IN
J
Temperature Stability
Output Amplitude
Over Operating Temperature Range
Pin 3, T = 25°C
%
3.5
0.5
3.5
0.5
V
J
Output Pulse Width
Error Amplifier Section
Input Offset Voltage
Input Bias Current
Open Loop Voltage Gain
Common Mode Voltage
C = .01mfd, T = 25°C
µs
T
J
V
V
= 2.5V
= 2.5V
0.5
2
5
2
2
10
10
mV
µA
dB
V
CM
CM
10
72
80
60
80
T = 25°C
J
1.8
3.4
1.8
3.4
2
UC1524
UC2524
UC3524
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = –55°C to +125°C
for the UC1524, –25°C to +85°C for the UC2524, and 0°C to +70°C for the UC3524, VIN = 20V, and f = 20kHz,
TA = TJ.
UC1524/UC2524
MIN MAX
UC3524
UNITS
PARAMETER
TEST CONDITIONS
MIN
MAX
Error Amplifier Section (cont.)
Common Mode Rejection Ratio T = 25°C
70
3
70
3
dB
MHz
V
J
Small Signal Bandwidth
Output Voltage
AV = 0dB, T = 25°C
J
T = 25°C
J
0.5
0
3.8
45
0.5
0
3.8
45
Comparator Section
Duty-Cycle
% Each Output On
Zero Duty-Cycle
%
V
Input Threshold
1
3.5
1
1
3.5
1
Maximum Duty-Cycle
V
Input Bias Current
Current Limiting Section
Sense Voltage
µA
Pin 9 = 2V with Error Amplifier
190
200
0.2
210
180
–1
200
0.2
220
+1
mV
Set for Maximum Out, T = 25°C
J
Sense Voltage T.C.
mV/°C
V
Common Mode Voltage
T = –55°C to 85°C
J
–1
+1
+1
for the –1V to 1V Limit
T = 125°C
J
–0.3
V
Output Section (Each Output)
Collector-Emitter Voltage
Collector Leakage Current
Saturation Voltage
40
17
40
17
V
µA
V
V
= 40V
0.1
1
50
2
0.1
1
50
2
CE
IC = 50mA
= 20V
Emitter Output Voltage
Rise Time
V
18
0.2
0.1
8
18
0.2
0.1
8
V
IN
RC = 2kΩ, T = 25°C
µs
µs
mA
J
Fall Time
RC = 2kΩ, T = 25°C
J
V
= 40V
10
10
Total Standby Current (Note)
IN
PRINCIPLES OF OPERATION
The UC1524 is a fixed-frequency pulse-width-modulation the appropriate output pass transistor (Q1 or Q2) by the
voltage regulator control circuit. The regulator operates at pulse-steering flip-flop, which is synchronously toggled by
a frequency that is programmed by one timing resistor the oscillator output. The oscillator output pulse also
(RT), and one timing capacitor (CT), RT establishes a serves as a blanking pulse to assure both outputs are
constant charging current for CT. This results in a linear never on simultaneously during the transition times. The
voltage ramp at CT, which is fed to the comparator provid- width of the blanking pulse is controlled by the valve of
ing linear control of the output pulse width by the error CT. The outputs may be applied in a push-pull configura-
amplifier. The UC1524 contains an on-board 5V regulator tion in which their frequency is half that of the base oscil-
that serves as a reference as well as powering the lator, or paralleled for single-ended applications in which
UC1524’s internal control circuitry and is also useful in the frequency is equal to that of the oscillator. The output
supplying external support functions. This reference volt- of the error amplifier shares a common input to the com-
age is lowered externally by a resistor divider to provide a parator with the current limiting and shutdown circuitry
reference within the common-mode range of the error and can be overridden by signals from either of these in-
amplifier or an external reference may be used. The puts. This common point is also available externally and
power supply output is sensed by a second resistor di- may be employed to control the gain of, or to compen-
vider network to generate a feedback signal to the error sate, the error amplifier or to provide additional control to
amplifier. The amplifier output voltage is then compared the regulator.
to the linear voltage ramp at CT. The resulting modulated
pulse out of the high-gain comparator is then steered to
3
UC1524
UC2524
UC3524
TYPICAL CHARACTERISTICS
Open-loop voltage amplification of error amplifier vs
frequency.
Oscillator frequency vs timing components.
Output dead time vs timing capacitance value.
Output saturation voltage vs load current.
4
UC1524
UC2524
UC3524
APPLICATION INFORMATION
Oscillator
amplifier. This can easily be done with the circuit in Fig-
ure 1:
The oscillator controls the frequency of the UC1524 and is
programmed by RT and CT according to the approximate Synchronous Operation
formula:
When an external clock is desired, a clock pulse of ap-
1.18
proximately 3V can be applied directly to the oscillator
output terminal. The impedance to ground at this point is
approximately 2kΩ. In this configuration RT CT must be
selected for a clock period slightly greater than that of the
external clock.
f ′
RT CT
where RT is in kΩ
where CT is in mF
where f is in kHz
If two or more UC1524 regulators are to operated synchro-
nously, all oscillator output terminals should be tied to-
gether, all CT terminals connected to single timing capacitor,
and the timing resistor connected to a single RT, terminal.
Practical values of CT fall between 0.001mF and 0.1mF.
Practical values of RT fall between 1.8kΩ and 100kΩ.
This results in a frequency range typically from 120Hz to
500kHz.
Blanking
16
9
V
REF
The output pulse of the oscillator is used as a blanking
pulse at the output. This pulse width is controlled by the
value of CT. If small values of CT are required for fre-
quency control, the oscillator output pulse width may still
be increased by applying a shunt capacitance of up to
100pF from pin 3 to ground. If still greater dead-time is re-
quired, it should be accomplished by limiting the maxi-
mum duty cycle by clamping the output of the error
1N916
COMP
5k
GND
8
Figure 1. Error amplifier clamp.
The other RT terminals can be left open or shorted to VREF
.
Minimum lead lengths should be used between the CT ter-
minals.
Figure 2. Single-ended LC switching regulator circuit.
5
UC1524
UC2524
UC3524
V+
+28 V
15
5 k
1 k
1 W
VIN
UC1524
5 k
1 k
1 W
1
2
INV INPUT
CA 12
EA 11
CB 13
EB 14
5 V
5 A
5 k
0.1
NON INV INPUT
2N4150
+
5 k
100
100
20T
20T
5T
5T
1500
F
F
16 VREF
2 k
6
7
3
RT
2N4150
0.1
F
CT
CLSENSE(+)
4
5
9
0.1
OSC OUT CLSENSE(-)
0.001
F
10 SD
COMP
GND
8
500
F
50 k
Figure 3. Push-pull transformer coupled circuit.
Figure 4. Open loop test circuit.
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 FAX (603) 424-3460
6
PACKAGE OPTION ADDENDUM
www.ti.com
8-Mar-2005
PACKAGING INFORMATION
Orderable Device
Status (1)
Package Package
Pins Package Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)
Qty
Type
CDIP
CDIP
CDIP
SOIC
SOIC
CDIP
PDIP
SOIC
SOIC
SOIC
SOIC
CDIP
PDIP
Drawing
UC1524J
UC1524J/80937
UC1524J883B
UC2524DW
UC2524DWTR
UC2524J
OBSOLETE
OBSOLETE
OBSOLETE
ACTIVE
J
J
16
16
16
16
16
16
16
16
16
16
16
16
16
None
None
None
None
None
None
None
None
None
None
None
None
None
Call TI
Call TI
Call TI
Call TI
Call TI
Call TI
J
DW
DW
J
40
CU NIPDAU Level-2-220C-1 YEAR
CU NIPDAU Level-2-220C-1 YEAR
ACTIVE
2000
OBSOLETE
ACTIVE
Call TI
Call TI
UC2524N
N
25
40
CU SNPB
Level-NA-NA-NA
UC3524D
ACTIVE
D
CU NIPDAU Level-1-220C-UNLIM
CU NIPDAU Level-1-220C-UNLIM
CU NIPDAU Level-2-220C-1 YEAR
CU NIPDAU Level-2-220C-1 YEAR
UC3524DTR
UC3524DW
UC3524DWTR
UC3524J
ACTIVE
D
2500
40
ACTIVE
DW
DW
J
ACTIVE
2000
OBSOLETE
ACTIVE
Call TI
Call TI
UC3524N
N
25
CU SNPB
Level-NA-NA-NA
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - May not be currently available - please check http://www.ti.com/productcontent for the latest availability information and additional
product content details.
None: Not yet available Lead (Pb-Free).
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Green (RoHS & no Sb/Br): TI defines "Green" to mean "Pb-Free" and in addition, uses package materials that do not contain halogens,
including bromine (Br) or antimony (Sb) above 0.1% of total product weight.
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDECindustry standard classifications, and peak solder
temperature.
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Addendum-Page 1
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