CHERRY Semiconductor CS51021, CS51023, CS51022, CS51024 Service Manual

The CS51021/22/23/24 Fixed
Frequency PWM Current Mode
Controller family provides all neces­sary features required for AC-DC or
DC-DC primary side control.
Several features are included elimi­nating the additional components
needed to implement them external­ly. In addition to low start-up cur­rent (75µA) and high frequency
operation capability, the CS51021/
22/23/24 family includes overvolt­age and undervoltage monitoring,
externally programmable dual

threshold overcurrent protection,
current sense leading edge blank­ing, current slope compensation,
accurate duty cycle control and an
externally available 5V reference.
The CS51021 and CS51023 feature
bidirectional synchronization capa­bility, while the CS51022 and
CS51024 offer a sleep mode with
100µA maximum IC current con­sumption. The CS51021/22/23/24
family is available in a 16 lead nar­row body SO package.

1

Features

■ 75µA Max. Startup Current

■ Fixed Frequency Current

Mode Control

■ 1MHz Switching Frequency

■ Undervoltage Protection

Monitor

■ Overvoltage Protection

Monitor with
Programmable Hysteresis

■ Programmable Dual

Threshold Overcurrent
Protection with Delayed
Restart

■ Programmable Soft Start

■ Accurate Maximum Duty

Cycle Limit

■ Programmable Slope

Compensation

■ Leading Edge Current

Sense Blanking

■ 1A Sink/Source Gate Drive

■ Bidirectional Synchronization

(CS51021/23)

■ 50ns PWM Propagation

Delay

■ 100µA Max Sleep Current

(CS51022/24)

Package Options

CS51021/22/23/24

Enhanced Current Mode

PWM Controller

CS51021/CS51023
CS51022/CS51024

Description

Typical Application Diagram

SS

V

REF

OV

SLEEP

or SYNC

V

FB

RTC

T

V

CC

SLOPE

I

SET

PGnd

I

SENSE

COMP

LGnd

UV

V

C

GATE

16 Lead SO Narrow

Device Sleep/Synch VCCStart/Stop

CS51021 Synch 8.25V/7.7V
CS51022 Sleep 8.25V/7.7V
CS51023 Synch 13V/7.7V
CS51024 Sleep 13V/7.7V

A Company

®

36-72V to 5V, 5A DC-DC Convertor

Rev. 2/22/99

Cherry Semiconductor Corporation

2000 South County Trail, East Greenwich, RI 02818

Tel: [phone] Fax: [phone]

Email: [e-mail]

Web Site: www.cherry-semi.com

Consult factory for other package options.

查询CS51021供应商

V

(36V to 72V)

IN

PGND

SYNC/SLEEP

0.01µF
10K

330pF

51k

11V

4700pF
51K

0.01µF

BAS21

18V

22µF

FZT688

22K

V

C

V

REF

COMP
V

FB

RTC
SYNC/

SLEEP

C

SS

LGnd

10

T

SLOPE

CS51021/51022

U1

GATE

I

SENSE

PGnd

V

CC

UV
OV

I

SET

100

1µF

100

100p

100:1

4:1

10K

100pF

10

62

0.1µF

470pF

24.3K
1%

6.98k,
1%

200K,1%

2.49K,1%
BA521

IRF6345

10

6.98k,
1%

MBRB2060CT

10

680pF

2:5

100µF

100µF

V

OUT

(5V/5A)

SGND

1

10K

0.1µF

5.1K

TL431

1000pF

180

1K

MOC81025

1K

2K, 1%

2K,1%

Power Supply Voltage, VCC............................................................................................................................................-0.3V, 20V

Driver Supply Voltage, V

C

..............................................................................................................................................-0.3V, 20V

SYNC, SLEEP, R

TCT

, SOFT START, VFB, SLOPE, I

SENSE

, UV, OV, I

SET

(Logic Pins).......................................-0.25V to V

REF

Peak GATE Output Current.........................................................................................................................................................1A

Steady State Output Current..................................................................................................................................................± 0.2A

Operating Junction Temperature, TJ..................................................................................................................................... 150°C

Storage Temperature Range, T

S

...................................................................................................................................-65 to 150°C

ESD (Human Body Model).........................................................................................................................................................2kV

Lead Temperature Soldering: Reflow (SMD styles only).............................................60 sec. max above 183°C, 230°C peak

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

2

CS51021/22/23/24

Absolute Maximum Ratings

■ Under Voltage Lockout

START Threshold (CS51021/22) 7.95 8.25 8.8 V
START Threshold (CS51023/24) 12.4 13 13.4 V
STOP Threshold 7.4 7.7 8.2 V
Hysteresis (CS51021/22) 0.50 0.75 1.00 V
Hysteresis (CS51023/24) 4 5 6 V
I

CC

@ Startup (CS51021/22) V

CC

< UV

START

Threshold 40 75 µA

I

CC

@ Startup (CS51023/24) V

CC

< UV

START

Threshold 45 75 µA

I

CC

Operating (CS51021/23) 7 9 mA

I

CC

Operating (CS51022/24) 6 8 mA

I

C

Operating Includes 1nF Load 7 12 mA

■ Voltage Reference

Initial Accuracy T

A

= 25C, I

REF

= 2mA, VCC= 14V (Note1) 4.95 5 5.05 V

Total Accuracy 1mA<I

REF

<10mA 4.9 5 5.15 V

Line Regulation 8.2V < V

CC

< 18V, I

REF

= 2mA 6 20 mV

Load Regulation 1mA < I

REF

< 10mA 6 15 mV

NOISE Voltage (Note 1) 50 uV
OP Life Shift T=1000 Hours (Note 1) 4 20 mV
FAULT Voltage Force V

REF

.92 × V

REF

.95 × V

REF

.97 × V

REF

V

OK Voltage Force V

REF

.94 × V

REF

.96 × V

REF

.98 × V

REF

V

OK Hysteresis Force V

REF

50 105 160 mV

Current Limit Force V

REF

-20 mA

■ Error Amplifier

Initial Accuracy T

A

=25°C, I

REF

= 2mA, V

CC

= 14V, 2.465 2.515 2.565 V

V

FB

= COMP (Note 1)

Reference Voltage V

FB

= COMP 2.440 2.515 2.590 V

V

FB

Leakage Current V

FB

= 0V -0.2 -2 µA

Open Loop Gain 1.4V < COMP < 4V (Note 1) 60 90 dB
Unity Gain Bandwidth (Note 1) 1.5 2.5 MHz
COMP Sink Current COMP = 1.5V, V

FB

= 2.7V 2 6 mA

COMP Source Current COMP = 1.5V, V

FB

= 2.3V -0.2 -0.5 mA

Electrical Characteristics: Unless otherwise stated, specifications apply for -40°C < TA< 85°C, -40°C < TJ< 150°C,

3V < V

C

< 20V, 8.2V < VCC< 20V, RT= 12kΩ, CT= 390pF.

3

CS51021/22/23/24

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Electrical Characteristics: -40°C < TA< 85°C, -40°C < TJ< 150°C, 3V < VC< 20V, 8.2V < VCC< 20V,

R

T

= 12kΩ, CT= 390pF, unless otherwise stated

■ Error Amplifier continued

COMP High Voltage V

FB

= 2.3V 4.35 4.8 5 V

COMP Low Voltage V

FB

= 2.7V 0.4 0.8 1.2 V

PS Ripple Rejection FREQ = 120Hz (Note 1) 60 85 dB
SS Clamp, V

COMP

VSS=2.5V, V

FB

= 0V, I

SET

= 2V 2.4 2.5 2.6 V

I

LIM(SET)

Clamp (Note 1) 0.95 1 1.15 V

■ Oscillator

Accuracy R

T

= 12k, CT= 390pF 230 255 280 kHz

Voltage Stability Delta Frequency 8.2V < V

CC

< 20V 2 3 %

Temperature Stability T

MIN

< TA < T

MAX

(Note1) 8 %

Min Charge & Discharge Time (Note1) 0.333 µs
Duty Cycle Accuracy R

T

= 12k, CT= 390pF 70 77 83 %

Peak Voltage (Note 1) 3 V
Valley Voltage (Note 1) 1.5 V
Valley Clamp Voltage 10k Resistor to ground on R

TCT

1.2 1.4 1.6 V

Discharge Current 0.8 1 1.2 mA
Discharge Current T

A

=25°C (Note 1) 0.925 1 1.075 mA

■ Synchronization (CS51021/23)

Input Threshold 1.0 1.5 2.7 V
Output Pulsewidth 160 260 360 ns
Output High Voltage I

SYNC

= 100µA 3.5 4.3 4.8 V

Input Resistance (Note 1) 35 70 140 kΩ
Drive Delay SYNC to GATE RESET 80 120 150 ns
Output Drive Current 1k Load 1.25 2 3.5 mA

■ SLEEP (CS51022/24)

SLEEP Input Threshold Active High 1.0 1.5 2.7 V
SLEEP Input Current V

SLEEP

= 4V 11 25 46 µA

I

CC

@ SLEEP V

CC

≤ 15V 50 100 µA

■ GATE Driver

HIGH Voltage Measure V

C

-GATE, VC = 10V, 150mA Load 1.5 2.2 V

LOW Voltage Measure GATE-PGnd, 150mA SINK 1.2 1.5 V
HIGH Voltage Clamp V

C

= 20V, 1nF 11 13.5 16 V

LOW Voltage Clamp Measured at 10mA Output Current 0.6 0.8 V
Peak Current V

C

= 20V, 1nF (Note 1) 1 A

UVL Leakage V

C

= 20V, measured at 0V -1 -50 µA

RISE Time Load = 1nF, 1V < GATE < 9V, 60 100 ns

V

C

= 20V, TA= 25˚C

FALL Time Load = 1nF, 9V > GATE > 1V, V

C

= 20V 15 40 ns