IP1844 [SEME-LAB]
CURRENT MODE REGULATING PULSE WIDTH MODULATORS; 电流模式调节脉宽调制器型号: | IP1844 |
厂家: | SEME LAB |
描述: | CURRENT MODE REGULATING PULSE WIDTH MODULATORS |
文件: | 总6页 (文件大小:61K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
IP1844 SERIES
IP1845 SERIES
SEME
LAB
TOP VIEW
CURRENT MODE
1
2
3
4
8
7
6
5
VREF
COMP
VCC
VFB
REGULATING
PULSE WIDTH
MODULATORS
ISENSE
RT /CT
OUTPUT
GROUND
J Package – 8 Pin Ceramic DIP
N Package – 8 Pin Plastic DIP
FEATURES
D-8 Package – 8 Pin Plastic (150) SOIC
• Guaranteed ±1% reference voltage tolerance
TOP VIEW
• Guaranteed ±10% frequency tolerance
14
13
12
11
10
9
1
2
3
4
5
6
7
VREF
COMP
N/C
µ
• Low start–up current (<500 A)
N/C
• Under voltage lockout with hysteresis
VFB
VCC
• Output state completely defined for all supply
and input conditions
N/C
VC
• Interchangeable with UC1844 and UC1845
series for improved operation
ISENSE
N/C
OUTPUT
GROUND
• 500kHz Oscillator operation
250kHz Output operation
POWER
GROUND
8
RT /CT
D-14 Package – 14 Pin Plastic (150) SOIC
Order Information
Part
Number
J–Pack
8 Pin
N–Pack
8 Pin
D–8
8 Pin
D–14
14 Pin
Temp.
Range
Note:
To order, add the package identifier to the
part number.
IP1844
IP2844
IP3844
IP1845
IP2845
IP3845
✔
✔
✔
✔
✔
✔
-55 to +125°C
-25 to +85°C
0 to +70°C
-55 to +125°C
-25 to +85°C
0 to +70°C
✔
✔
✔
✔
✔
✔
eg.
IP1844D–14
IP3845J
✔
✔
✔
✔
✔
✔
ABSOLUTE MAXIMUM RATINGS (T
= 25°C unless otherwise stated)
case
(low impedance source)
V
Supply Voltage
+30V
Self limiting
CC
(I < 30mA)
CC
I
Output Current
±1A
O
Output Energy
(capacitive load)
(pins 2 and 3)
5µJ
Analog Inputs
–0.3V to +V
10mA
CC
Error Amp Output Sink Current
Power Dissipation
P
P
P
T
T
T
= 25°C
= 25°C
= 25°C
J, N Packages
D Package
1W
10mW/°C
D
D
D
amb
case
case
Derate @ T
> 50°C
amb
Power Dissipation
Derate @ T > 50°C
725mW
7.25mW/°C
amb
Power Dissipation
Derate @ T > 25°C
J, N Packages
2W
16mW/°C
case
T
T
Storage Temperature Range
Lead Temperature
–65 to 150°C
+300°C
STG
(soldering, 10 seconds)
L
Prelim. 2/95
Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612.
IP1844 SERIES
IP1845 SERIES
SEME
LAB
DESCRIPTION
The IP1844 and IP1845 series of switching regulator control circuits contain all the functions necessary to
implement off-line, current mode switching regulators, using a minimum number of external parts.
Functions included are voltage reference, error amplifier, current sense comparator, oscillator, totem-pole output
driver and under-voltage lockout circuitry. In addition there is a toggle flip-flop which blanks the output on every
second clock pulse, thereby ensuring that the duty cycle never exceeds 50%.
Although pin compatible with the UC1844 and UC1845 series, SEMELAB has incorporated several improvements
in the IP1844 and IP1845 series allowing tighter and more complete specification of electrical performance .
BLOCK DIAGRAM
7/12
VCC
UNDER–VOLTAGE
LOCKOUT
34V
8/14
ENABLE
5V
REFERENCE
REGULATOR
V
REF
5/9
GND
16V
(8.4V)
INTERNAL
BIAS
6V
(0.5V)
2.5V
REG
VREF STATUS
LATCH
S
R
7/11VC
3.6V
4/7
6/10OUTPUT
RT /CT
OSCILLATOR
Q
TOGGLE
FLIP
FLOP
5/8
POWER
GROUND
T
ERROR
AMP
S
R
2R
2/3
1/1
PWM
LATCH
VFB
R
1V
C
OMP
Values in brackets are for IP1845 series.
CURRENT
SENSE
COMPARATOR
PIN NUMBERS
1st Number – N, J and 8 Pin D Packages
2nd Number – 14 Pin D Package.
3/5
ISENSE
RECOMMENDED OPERATING CONDITIONS
V
Supply Voltage
Output Current
Analog Inputs
≤ 30V
CC
I
0 to ±200mA
–0.3V to 3V
0 to 2mA
O
(pins 2 and 3)
Error Amp Output Sink Current
IP1844 , IP1845
IP2844 , IP2845
IP3844 , IP3845
–55 to 125°C
–25 to 85°C
0 to 70°C
Operating Ambient Temperature Range
Prelim. 2/95
Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612.
IP1844 SERIES
IP1845 SERIES
SEME
LAB
ELECTRICAL CHARACTERISTICS (Over Full Operating Temperature Range unless otherwise stated)
IP1844/IP1845
IP2844/IP2845
IP3844
IP3845
Typ.
Parameter
Test Conditions
Min.
Typ.
Max.
Min.
Max. Units
REFERENCE SECTION
Output Voltage
Input Regulation
Output Regulation
I
O = 1mA
CC = 12V to 25V
O = 1mA to 20mA
TJ = 25°C
4.95
5.00
6
5.05
20
4.90
5.00
6
5.10
20
V
V
mV
I
6
25
6
25
mV
°C
Temperature Stability
0.2
0.4
0.2
0.4
Total Output Variation
Output Noise Voltage
Long Term Stability
Output Short Circuit
Current
Line, Load, Temp
f = 10Hz to 10kHz
4.90
5.10
4.82
5.18
V
TJ = 25°C
50
5
50
5
µV
mV
TJ = 125°C @ 1000Hrs
25
25
V
REF = 0
30
47
80
160
30
47
80
160
mA
OSCILLATOR SECTION
Frequency
TJ = 25°C
52
0.2
5
57
1
52
0.2
5
57
1
kHz
%
Voltage stability
Temperature Stability
Amplitude
V
CC = 12V to 25V
∆TA = Min to Max
PIN4 Peak to Peak
%
V
1.7
8.3
8
1.7
8.3
8
V
TJ = 25°C
mA
%
Discharge Current
∆TA = Min to Max
ERROR AMP SECTION
Input Voltage
VPIN1 = 2.5V
2.45
2.50
–0.3
2.55
–1
2.42
2.50
–0.3
2.58
–2
V
Input Bias Current
Open Loop Voltage
Gain
µA
VO = 2V to 4V
65
0.7
60
90
1
65
0.7
60
90
1
dB
MHz
dB
Unity Gain Bandwidth
Supply Voltage
Rejection
VCC = 12V to 25V
70
70
Output Sink Current
Output Source Current
VPIN2 = 2.7V
VPIN2 = 2.3V
VPIN2 = 2.3V
VPIN2 = 2.7V
VPIN1 = 1.1V
VPIN1 = 5.0V
RL = 15kΩ
2
6
2
6
mA
V
–0.5
5.0
–0.8
6.0
0.7
–0.5
5.0
–0.8
6.0
0.7
V
V
OUT High
OUT Low
RL = 15kΩ
1.1
1.1
NOTES
1. Test Conditions unless otherwise stated:
CC = 15V* , RT = 10kΩ , CT = 3.3nF , f = 52kHz.
V
*Adjust VCC above start threshold before setting at required level.
All specifications apply over the full operating temperature range
unless otherwise stated. (See Ordering Information for further details).
Prelim. 2/95
Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612.
IP1844 SERIES
IP1845 SERIES
SEME
LAB
ELECTRICAL CHARACTERISTICS (Over Full Operating Temperature Range unless otherwise stated)
IP1844/IP1845
IP2844/IP2845
IP3844
IP3845
Typ.
Parameter
Test Conditions
Min.
Typ.
Max.
Min.
Max. Units
CURRENT SENSE SECTION
Gain
See Notes 2,3
2.85
0.9
3
1
3.15
1.1
2.85
0.9
3
1
3.15
1.1
V/V
V
Maximum Input Signal
Supply Voltage
Rejection
VPIN1 = 5.0V
(Note 2)
VC = 12V to 25V
60
70
60
70
dB
Input Bias Current
Delay to Output
–2
–10
300
–2
–10
300
µA
150
150
ns
OUTPUT SECTION
ISINK = 20mA
0.1
1.5
13.5
13.5
50
0.4
2.2
0.1
1.5
13.5
13.5
50
0.4
2.2
Output Low Level
Output High Level
V
V
I
I
I
SINK = 200mA
SOURCE = 20mA
SOURCE = 200mA
13
12
13
12
Rise Time
CL = 1nF
CL = 1nF
150
150
1.1
150
150
1.1
ns
V
Fall Time
50
50
UVLO Saturation
VCC = 6V
IL = 1mA
0.7
0.7
UNDER–VOLTAGE LOCKOUT SECTION
Upper Threshold
1844 Series
15
7.8
9
16
8.4
10
17
9
14.5
7.8
8.5
7
16
8.4
10
17.5
9
V
V
(VCC
Lower Threshold
(VCC
)
1845 Series
1844 Series
11
8.2
11.5
8.2
)
1845 Series
7
7.6
7.6
TOTAL STANDBY CURRENT
Start–up Current
Operating Supply
Current
0.3
11
14
34
0.5
15
17
40
0.3
11
14
34
0.5
15
17
40
mA
mA
V
V
PIN2 = 0V
PIN3 = 0V
1844 Series
1845 Series
V
VCC Zener Voltage
I
CC = 25mA
30
47
30
46
PWM SECTION
Maximum Duty Cycle
Minimum Duty Cycle
48
50
0
48
50
0
%
NOTES
1. Test Conditions unless otherwise stated:
CC = 15V* , RT = 10kΩ , CT = 3.3nF , f = 52kHz.
2. Parameter measured at trip point of latch with
V
V
= 0V
PIN2
*Adjust VCC above start threshold before setting at
required level.
3. Gain defined as:
∆V
∆V
PIN1
PIN3
A =
0 ≤ V
≤ 0.8
All specifications apply over the full operating temperature
range unless otherwise stated.
PIN3
(See Ordering Information for further details).
Prelim. 2/95
Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612.
IP1844 SERIES
IP1845 SERIES
SEME
LAB
APPLICATIONS INFORMATION
Oscillator Waveforms and Maximum Duty Cycle
LARGE R T
SMALL C T
V - Pin 4
(Pin 7 for 14 Pin D Package)
Internal Clock
VREF
R T C T
GND
8
4
5
R T
Output – Max. Duty Cycle
V - Pin 6
(Pin 10 for 14 Pin D Package)
C T
SMALL R T
LARGE C T
V - Pin 4
(Pin 7 for 14 Pin D Package)
Internal Clock
Output – Max. Duty Cycle
V - Pin 6
(Pin 10 for 14 Pin D Package)
Oscillator timing capacitor C is charged by V
through R and discharged by an
T
T
REF
internal current source. During the discharge time, the internal clock signal blanks the
output to the low state. Selection of R and C therefore determines both oscillator
T
T
frequency and maximum duty cycle.
Charge and discharge times are determined by the formulae:
t ≈ 0.55 RTCT
For RT > 5kΩ,
c
.0063 R – 2.3
1.8
(RTCT)
T
t ≈ RTCT Rn
Resultant frequency f ≈
d
(
)
.0063 – 4
1
Resultant frequency f =
(t + t )
c
d
Prelim. 2/95
Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612.
IP1844 SERIES
IP1845 SERIES
SEME
LAB
APPLICATIONS INFORMATION
Open–Loop Laboratory Test Fixture
VREF
R T
VCC
4.7k
1k
Ω
Ω
2N2222
1
2
3
4
8
7
6
5
COMP
VREF
0.1
100k
Ω
µ
F
0.1
VFB
VCC
ERROR AMP
ADJUST
µ
F
1k
Ω
1kW
5k
Ω
ISENSE
ISENSE
O/P
OUTPUT
GROUND
ADJUST
4.7k
Ω
R T /C T
GND
C T
High peak current associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should
be connected close to pin 5 in a single point ground. The transistor and 5K potentiometer are used to sample the oscillator wave
form and apply an adjustable ramp to pin 3.
TYPICAL PERFORMANCE CHARACTERISTICS
ERROR AMPLIFIER OPEN-LOOP
OUTPUT SATURATION CHARACTERISTICS
FREQUENCY RESPONSE
4
3
2
1
0
100
80
60
40
20
0
0
VCC = 15V
TA = 25˚C
TA = –55˚C
–45
–90
–135
–180
SOURCE SAT (VCC- VOH
)
AV
SINK SAT (VOL
)
10
100
1k
10k
100k
1M
10M
.01
.02
.03 .04 .05
.07
.1
.2
.3
.4 .5
.7
1.0
OUTPUT CURRENT, SOURCE / SINK (A)
FREQUENCY (Hz)
UNDER VOLTAGE LOCKOUT
1844 SERIES
UNDER VOLTAGE LOCKOUT
1845 SERIES
20
15
10
0.5
0
20
15
10
0.5
0
0
5
10
15
20
0
2.5
5
7.5
10
VCC (V)
VCC (V)
Prelim. 2/95
Semelab plc. Telephone (01455) 556565. Telex: 341927. Fax (01455) 552612.
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