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부품번호 | CS2841B 기능 |
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기능 | Automotive Current Mode PWM Control Circuit | ||
제조업체 | Cherry Semiconductor Corporation | ||
로고 | |||
전체 6 페이지수
CS2841B
Automotive Current Mode PWM
Control Circuit
Description
Features
The CS2841B provides all the nec-
essary features to implement off-
line fixed frequency current-mode
control with a minimum number of
external components.
The CS2841B (a variation of the
CS-2843A) is designed specifically
for use in automotive operation.
The low start threshold voltage of
8.0V (typ), and the ability to sur-
vive 40V automotive load dump
transients are important for auto-
motive subsystem designs. The
CS-2841 series has a history of
quality and reliability in automo-
tive applications.
The CS2841B incorporates a preci-
sion temperature-controlled oscil-
lator with an internally trimmed
discharge current to minimize vari-
ations in frequency. Duty-cycles
greater than 50% are also possible.
On board logic ensures that VREF is
stabilized before the output stage
is enabled. Ion implant resistors
provide tighter control of under-
voltage lockout.
Absolute Maximum Ratings
Supply Voltage (Low Impedance Source)...................................................40V
Output Current ...............................................................................................±1A
Output Energy (Capacitive Load) .................................................................5µJ
Analog Inputs (VFB, Sense) ............................................................-0.3V to 5.5V
Error Amp Output Sink Current...............................................................10mA
Lead Temperature Soldering
Wave Solder (through hole styles only) ..........10 sec. max, 260°C peak
Reflow (SMD styles only) ...........60 sec. max above 183°C, 230°C peak
Block Diagram
s Optimized for Off-line
Control
s Internally Trimmed
Temperature
Compensated Oscillator
s Maximum Duty-cycle
Clamp
s VREF Stabilized before
Output Stage Enabled
s Low Start-up Current
s Pulse-by-pulse Current
Limiting
s Improved Undervoltage
Lockout
s Double Pulse Suppression
s 1% Trimmed Bandgap
Reference
s High Current Totem Pole
Output
Package Options
8 Lead PDIP
VCC
Gnd
OSC
VFB
COMP
Sense
Undervoltage
Lock-out Circuit
8.0V/7.4V
Set/
5V
Reset Reference
2.50V
Oscillator
Output
Enable
Internal
Bias
NOR
+
–
Error
VC
Amplifier
2R
R
S
R
1 V Current
Sensing
Comparator
PWM
Latch
VCC Pwr
VREF
VOUT
Pwr Gnd
COMP 1
VFB 2
Sense 3
OSC 4
8 VREF
7 VCC
6 VOUT
5 Gnd
14 Lead SO Narrow
COMP 1
NC 2
VFB 3
NC 4
Sense 5
NC 6
OSC 7
14 VREF
13 NC
12 VCC
11 VCC Pwr
10 VOUT
9 Pwr Gnd
8 Gnd
Rev. 6/23/99
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: [email protected]
Web Site: www.cherry-semi.com
1 A ® Company
Typical Performance Characteristics:
Oscillator Frequency vs CT
Oscillator Duty Cycle vs RT
900
800
RT =680Ω
700
600
500
RT =1.5kΩ
400
300
200
RT =10kΩ
100
.0005
.001
.002 .003 .005
CT (µF)
.01
100
90
80
70
60
50
40
30
20
10
.02 .03 .04 .05
100 200 300 400 500 700 1k
2k 3k 4k 5k 7k 10k
RT (Ω)
Test Circuit
4.7kΩ
1kΩ
Error Amp
Adjust
4.7kΩ
RT
2N2222
100kΩ
COMP
5kΩ
Sense
Adjust
VFB
Sense
OSC
VREF
VCC
V O UT
Gnd
0.1µF
A
0.1µF
1kΩ
1W
VREF
VCC
VO
Gnd
CT
Circuit Description
VCC
ON/OFF Command
to reset of IC
VON = 8.0V
VOFF= 7.4V
ICC
<15mA
<1mA
7.4V 8.0V
Figure 1: Typical Undervoltage Characteristics
VCC
Undervoltage Lockout
During Undervoltage Lockout (Figure 1), the output driv-
er is biased to a high impedance state. The output should
be shunted to ground with a resistor to prevent output
leakage current from activating the power switch.
PWM Waveform
To generate the PWM waveform, the control voltage from
the error amplifier is compared to a current sense signal
which represents the peak output inductor current (Figure
2). An increase in VCC causes the inductor current slope to
increase, thus reducing the duty cycle. This is an inherent
feed-forward characteristic of current mode control, since
the control voltage does not have to change during
changes of input supply voltage.
When the power supply sees a sudden large output cur-
rent increase, the control voltage will increase allowing the
duty cycle to momentarily increase. Since the duty cycle
tends to exceed the maximum allowed to prevent trans-
4
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다운로드 | [ CS2841B.PDF 데이터시트 ] |
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구매 문의 | 일반 IC 문의 : 샘플 및 소량 구매 ----------------------------------------------------------------------- IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한 광범위한 전력 반도체를 판매합니다. 전력 반도체 전문업체 상호 : 아이지 인터내셔날 사이트 방문 : [ 홈페이지 ] [ 블로그 1 ] [ 블로그 2 ] |
부품번호 | 상세설명 및 기능 | 제조사 |
CS2841B | Automotive Current Mode PWM Control Circuit | Cherry Semiconductor Corporation |
CS2841B | Automotive Current Mode PWM Control Circuit | ON Semiconductor |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |