UC3846_15_技术文档

UNISONIC TECHNOLOGIES CO., LTD

UC3846

LINEAR INTEGRATED CIRCUIT

CURRENT MODE PWM

CONTROLLER

DIP-16



DESCRIPTION

The UTC UC3846 control IC offers all necessary features for

accomplishment of fixed frequency, current mode control functions,

however it contains the least external parts. The performance of this

technique is superior to the others in better line regulation,

enhanced load response characteristics while designing a simpler

and easier control loop for design. It owns topological advantages of

inherent pulse-by-pulse current limiting, automatic symmetry

correction for push-pull converters, and the ability to parallel “power

modules" for equal current sharing.

SOP-16

SOP-16W

Protection loop includes soft start, built-in under-voltage lockout

and programmable current limit. The shutdown circuitry can

provide either a complete shutdown with automatic restart or the

supply off-latch.

In addition, many other features can also be available, including

fully latched operation, double pulse suppression, deadline adjust,

and a ±1% trimmed bandgap reference.

The UTC UC3846 features low outputs in the OFF state.



FEATURES

* Built-in under-voltage lockout

* Soft start

* Shutdown function

* Improved load response characteristics

* Parallel operation capability for modular power systems

* Differential current sense amplifier with wide common mode

range

* 500kHZ operation

* Feed forward compensation

* ±1% bandgap reference

* Programmable pulse-by-pulse current limiting

* Double pulse suppression

* 500mA (Peak) totem-pole outputs

* Automatic symmetry correction in push-pull configuration



ORDERING INFORMATION

Ordering Number

Lead Free

Package

Packing

Halogen Free

UC3846L-D16-T

UC3846L-S16-T

UC3846L-S16-R

UC3846L-S16W-T

UC3846L-S16W-R

UC3846G-D16-T

UC3846G-S16-T

UC3846G-S16-R

UC3846G-S16W-T

UC3846G-S16W-R

DIP-16

SOP-16

Tube

SOP-16

Tape Reel

Tube

SOP-16W

Tape Reel

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UC3846

LINEAR INTEGRATED CIRCUIT



PIN CONFIGURATION

C/S SS

V_REF

1

2

3

4

5

6

7

8

16 Shutdown

15 V_IN

C/S-

14 B Out

13 V_C

C/S+

E/A+

E/A-

12 GND

11 A Out

10 Sync

COMP

C_T

9

R_T



PIN DESCRIPTION

PIN NO.

PIN NAME

C/S SS

V_REF

DESCRIPTION

1

2

Adjustment of Current Limiting

Internal Reference Voltage

3

C/S-

Forward Input of Current Limiting

Backward Input of Current Limiting

Forward Input of Error Amplifier

Backward Input of Error Amplifier

Output of Error Amplifier

4

C/S+

E/A+

E/A-

5

6

7

COMP

C_T

8

External Capacity for Frequency

External Resistor for Frequency

9

R_T

10

11

12

13

14

15

16

SYNC

A OUT

GND

V_C

Synchronization for Frequency of Oscillator

Dual Output A

Ground

Power Supply of the Collector

Dual Output B

B OUT

V_IN

DC Power Supply Input

SHUTDOWN Shutdown Controller

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UC3846

LINEAR INTEGRATED CIRCUIT



BLOCK DIAGRAM

2

V_IN

V_REF

VC

V_REF

15

13

SYNC

RT

UVLO

LOCKOUT

10

9

Q

11 A OUT

T

OSC

DUAL

CT

8

OUTPUT

3

4

C/S-

-

+

-

A

S

R

Q

COMP

C/S+

+

14

12

B OUT

GND

0.5V

0.5mA

E/A+

E/A-

+

EA

-

5

6

C/S SS

1

+

-

16

SHUTDOWN

COMP

7

350mV

6KΩ

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UC3846

LINEAR INTEGRATED CIRCUIT



ABSOLUTE MAXIMUM RATING (Note)

PARAMETER

SYMBOL

V_IN

RATINGS

+40

UNIT

V

Supply Voltage (Pin 15)

Collector Supply Voltage (Pin 13)

Output Current, Source or Sink (Pins 11, 14)

Analog Inputs (Pins 3, 4, 5, 6, 16)

Reference Output Current (Pin 2)

Sync Output Current (Pin 10)

V_C

+40

V

I_O

500

mA

V

V_A

-0.3~+V_IN

-30

I_REF

mA

mW

°C

I_SYNC-OUT

I_O-EA

I_SINK

I_OSC

-5

Error Amplifier Output Current (Pin 7)

Soft Start Sink Current (Pin 1)

-5

50

Oscillator Charging Current (Pin 9)

5

T_A=25°C

Power Dissipation

1000

2000

-65~+150

P_D

T_C=25°C

Storage Temperature

T_STG

Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.

Absolute maximum ratings are stress ratings only and functional device operation is not implied.



ELECTRICAL CHARACTERISTICS

(T_J=T_A=0°C~+70°C, V_IN=15V, R_T=10k, C_T=4.7nF, Unless otherwise specified)

PARAMETER

REFERENCE SECTION

Output Voltage

SYMBOL

TEST CONDITIONS

MIN TYP MAX UNIT

V_REF

∆V₁

∆V₂

V_S

T_J=25°C, I_O=1mA

5.0

5.1

5

5.2

20

15

V

mV

mV/°C

V

Line Regulation

V_IN=8V~40V

Load Regulation

I_L=1mA~10mA

3

Temperature Stability

Total Output Variation

Output Noise Voltage

Long Term Stability

Short Circuit Output Current

OSCILLATOR SECTION

Initial Accuracy

Over Operating Range, (Note 2)

Line, Load, and Temperature (Note 2)

10Hz≤f≤10kHz, T_J=25°C (Note 2)

T_J=125°C, 1000 Hrs. (Note 2)

V_REF=0V

0.4

V_REF-O

V_N

4.95

5.25

100

5

µV

∆V₃

I_S

mV

mA

-10

39

-45

F_OSC

∆V

T_J=25°C

43

-1

47

2

kHz

%

V

Voltage Stability

V_IN=8V~40V

Temperature Stability

Sync Output High Level

Sync Output Low Level

Sync Input High Level

Sync Input Low Level

Sync Input Current

ERROR AMP SECTION

Input Offset Voltage

Input Bias Current

∆T_S

Over Operating Range (Note 2)

-1

V_OH(SYNC)

V_OL(SYNC)

3.9

4.35

2.3

2.5

V

V_IH(SYNC)Pin 8=0V

V_IL(SYNC)Pin 8=0V

V

2.5

1.5

V

I_SYNC

Sync Voltage=3.9V, Pin 8=0V

1.3

mA

V_IO

I_BIAS

I_IO

0.5

-0.6

40

10

-2

mV

µA

nA

V

Input Offset Current

Common Mode Range

Open Loop Voltage Gain

Unity Gain Bandwidth

CMRR

250

V_CM

G_VO

B

V_IN=8V~40V

0

80

0.7

75

80

2

V_IN-2V

ꢀV_O=1.2~3V, V_CM=2V

T_J=25°C (Note 2)

105

1.0

100

105

6

dB

MHz

dB

mA

V

CMRR_AV_CM=0V~38V, V_IN=40V

PSRR

PSRR_A

I_SINK

V_IN=8V~40V

Output Sink Current

Output Source Current

High Level Output Voltage

Low Level Output Voltage

V_ID=-15mV~-5V, V_{PIN 7}=1.2V

V_ID=15mV~5V, V_{PIN 7}=2.5V

I_SOURCE

V_OH

-0.2

4.3

-0.5

4.6

0.7

R_L=(Pin 7) 15kΩ

V_OL

1

V

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UC3846

LINEAR INTEGRATED CIRCUIT



ELECTRICAL CHARACTERISTICS(Cont.)

PARAMETER

SYMBOL

TEST CONDITIONS

MIN TYP MAX UNIT

CURRENT SENSE AMPLIFIER SECTION

Amplifier Gain

G_A

V_IN(MAX)

V_IO

V_{PIN 3}=0V, Pin 1 Open (Note 3, 4)

Pin 1 Open (Note 3), R_L(Pin 7)=15kW

V_{PIN 1}=0.5V, Pin 7 Open (Note 3)

2.5

1.1

2.75

1.2

3.0

25

V

Maximum Differential Input

Signal (V_{PIN 4}-V_{PIN 3}

)

Input Offset Voltage

CMRR

5

mV

dB

µA

V

CMRR_AV_CM=1V~12V

60

83

PSRR

PSRR_A

I_BIAS

I_IO

V_IN=8V~40V

84

Input Bias Current

Input Offset Current

Input Common Mode Range

Delay to Outputs

V_{PIN 1}=0.5V, Pin 7 Open (Note 3)

-2.5

0.08

-10

1

∆V_R

t_D

0

V_IN-3

500

T_J=25°C, (Note 2)

200

ns

CURRENT LIMIT ADJUST SECTION

V

_{PIN 3}=0V, V_{PIN 4}=0V, Pin 7 Open

Current Limit Offset

V_L

I_B

0.45

0.5

-10

0.55

-30

V

(Note 3)

Input Bias Current

V_{PIN 5}=VREF,V_{PIN 6}=0V

µA

SHUTDOWN TERMINAL SECTION

Threshold Voltage

Input Voltage Range

Minimum Latching Current

(I_PIN1)

V_TH

250

0

350

1.5

550

V_IN

mV

V

∆V_SHUT

I_LATCH

(Note 6)

3.0

mA

Maximum Non-Latching

Current (I_PIN1)

I_NONLATCH(Note 7)

1.5

0.8

mA

ns

Delay to Outputs

t_D-SHUT

T_J=25°C (Note 2)

300

600

OUTPUT SECTION

Collector-Emitter Voltage

Collector Leakage Current

V_T

I_L

40

V

µA

V

V_C=40V (Note 5)

I_SINK=20mA

200

0.4

2.1

V_OL1

V_OL2

V_OH1

V_OH2

t_R

0.1

0.4

13.5

13.2

50

Output Low Level

Output High Level

I_SINK=100mA

V

I_SOURCE=20mA

13

12

V

I_SOURCE=100mA

V

Rise Time

Fall Time

C_L=1nF, T_J=25°C (Note 2)

300

ns

t_F

50

UNDER-VOLTAGE LOCKOUT SECTION

Start-Up Threshold

V_START

V_H

7.7

8.0

21

V

Threshold Hysteresis

TOTAL STANDBY CURRENT

Supply Current

0.75

I_T

17

mA

Notes: 1. All voltages are with respect to Ground, Pin 13. Currents are positive into, negative out of the speficied

terminal.

2. These parameters are not 100% tested in production, although guaranteed over the recommended

operating conditions

3. Parameter measured at trip point of latch with V_{PIN 5}=V_REF, V_{PIN 6}=0V.

∆V_PIN7

∆V_PIN4

4.

Amplifier gain defined as: G=

, V_PIN4=0~1.0V

5. Applies to UTC UC3846 only due to polarity of outputs.

6. Current into Pin 1 guaranteed to latch circuit in shutdown state.

7. Current into Pin 1 guaranteed not to latch circuit in shutdown state.

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UC3846

LINEAR INTEGRATED CIRCUIT



TEST CIRCUIT

I_S

(+)4

(-)3

R_S

I_SENSE

A

Comp

-

+

V_REF

0.5mA

0.5V

R1

EA

1

Current

Limit

R2

Comp

7

R2 V_REF

R1+R2

3R_S

-0.5

Peak Current (Is) is determined by the formula: IS=

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UC3846

LINEAR INTEGRATED CIRCUIT



TEST CIRCUIT(Cont.)

V_REF

I_SENSE

Comp

S

R1

Current

Limit

1

0.5

EA

C^*

R2

V_REF

16 Shutdown

-

+

350mV

Shutdown Without Auto-Restart

(Latched)

Shutdown With Auto-Restart

Current Limit

(Pin 1)

0.5V

0

Shutdown

(Pin 16)

ON

OFF

PWM

V_REF

R1

V_REF

(Latched Off)

> 3mA

< 0.8mA

R1

V_REF

R1

V_REF

R1

> 3mA, the device will

latch off until power is recycled.

If

< 0.8mA, the shutdown latch will commutate when

If

I_SS=0.8mA and a restart cycle will be initiated.

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UC3846

LINEAR INTEGRATED CIRCUIT



TYPICAL APPLICATION CIRCUIT

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UC3846

LINEAR INTEGRATED CIRCUIT



TYPICAL CHARACTERISTICS

Rising Time

Falling Time

V_IN&V_DD=15V, A_OUT=1nF,

C_T=4.7nF, R_T=10KΩ, output rise

time from 10%~ 90%.

V_IN&V_DD=15V,A_OUT=1nF,

C_T=4.7nF, R_T=10KΩ, output fall

time from 90%~ 10%.

0

500

1000

0

500

1000

Time (100ns/div)

Voltage Stability

V_IN=40V, C_T=4.7nF,

R_T=10KΩ, no effect on

the frequency

V_IN=8V, C_T=4.7nF,

R_T=10KΩ

0

50

100

0

50

100

Time (10µs/div)

UTC assumes no responsibility for equipment failures that result from using products at values that

exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or

other parameters) listed in products specifications of any and all UTC products described or contained

herein. UTC products are not designed for use in life support appliances, devices or systems where

malfunction of these products can be reasonably expected to result in personal injury. Reproduction in

whole or in part is prohibited without the prior written consent of the copyright owner. The information

presented in this document does not form part of any quotation or contract, is believed to be accurate

and reliable and may be changed without notice.

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型号：	UC3846_15
厂家：	Unisonic Technologies
描述：	CURRENT MODE PWM CONTROLLER
文件：	总9页 (文件大小：353K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

UC3846_15 [UTC]

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