UC2847L_技术文档

application

INFO

UC1846/7

UC2846/7

UC3846/7

available

Current Mode PWM Controller

FEATURES

DESCRIPTION

•

Automatic Feed Forward Compensation

The UC1846/7 family of control ICs provides all of the necessary

features to implement fixed frequency, current mode control

schemes while maintaining a minimum external parts count. The

superior performance of this technique can be measured in im-

proved line regulation, enhanced load response characteristics, and

a simpler, easier-to-design control loop. Topological advantages in-

clude inherent pulse-by-pulse current limiting capability, automatic

symmetry correction for push-pull converters, and the ability to par-

allel “power modules" while maintaining equal current sharing.

•

Programmable Pulse-by-Pulse Current

Limiting

•

Automatic Symmetry Correction in Push-pull

Configuration

•

Enhanced Load Response Characteristics

Parallel Operation Capability for Modular

Power Systems

Protection circuitry includes built-in under-voltage lockout and pro-

grammable current limit in addition to soft start capability. A shut-

down function is also available which can initiate either a complete

shutdown with automatic restart or latch the supply off.

•

Differential Current Sense Amplifier with

Wide Common Mode Range

•

Double Pulse Suppression

500mA (Peak) Totem-pole Outputs

1% Bandgap Reference

Under-voltage Lockout

Soft Start Capability

Other features include fully latched operation, double pulse sup-

pression, deadline adjust capability, and a 1% trimmed bandgap

reference.

The UC1846 features low outputs in the OFF state, while the

UC1847 features high outputs in the OFF state.

Shutdown Terminal

500kHZ Operation

BLOCK DIAGRAM

5.1 V

VIN 15

REFERENCE

REGULATOR

2

VREF

13 VC

SYNC 10

UVLO

LOCKOUT

F/F

RT

CT

9

8

Q

11 A OUT

T

OSC

Q

UC1846

Output Stage

C/S-

3

4

COMP

0.5 V

X3

UC1847

Output Inverted

S

R

Q

C/S+

14 B OUT

+

0.5 mA

12 GND

NI

5

6

E/A

INV

CURRENT

LIMIT ADJUST

1

16 SHUTDOWN

COMP

7

350 mV

6 k

UDG-02057

SLUS352A - JANUARY 1997 - REVISED MARCH 2002

UC1846/7

UC2846/7

UC3846/7

ABSOLUTE MAXIMUM RATINGS (Note 1)

Supply Voltage (Pin 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +40V

Collector Supply Voltage (Pin 13) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +40V

Output Current, Source or Sink (Pins 11, 14) . . . . . . . . . . . . . . . . . . . . . . . 500mA

Analog Inputs (Pins 3, 4, 5, 6, 16). . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +V_IN

Reference Output Current (Pin 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -30mA

Sync Output Current (Pin 10). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -5mA

Error Amplifier Output Current (Pin 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -5mA

Soft Start Sink Current (Pin 1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA

Oscillator Charging Current (Pin 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5mA

Power Dissipation at TA=25°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000mW

Power Dissipation at TC=25°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2000mW

Storage Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . -65°C to +150°C

Lead Temperature (soldering, 10 seconds) . . . . . . . . . . . . . . . . . . . . . . . . +300°C

Note 1. All voltages are with respect to Ground, Pin 13. Currents are positive into,

negative out of the speficied terminal. Consult Packaging Section of Databook for

thermal limitations and considerations of packages. Pin numbers refer to DIL and

SOIC packages only.

CONNECTION DIAGRAMS

DIL-16, SOIC-16

PLCC-20, LCC-20

(TOP VIEW)

Q, L Packages

PACKAGE PIN FUNCTION

(TOP VIEW)

FUNCTION

J or N Package, DW Package

N/C

1

C/L SS

VREF

C/S-

C/S+

N/C

2

3

4

5

6

E/A+

E/A-

Comp

CT

N/C

RT

Sync

A Out

Gnd

N/C

VC

7

8

9

10

11

12

13

14

15

16

17

18

19

20

B Out

VIN

Shutdown

(Unless otherwise stated, these specifications apply for TA=-55°C to +125°C for

UC1846/7; -40°C to +85°C for the UC2846/7; and 0°C to +70°C for the UC3846/7;

VIN=15V, RT=10k, CT=4.7nF, TA=TJ.)

ELECTRICAL CHARACTERISTICS

UC1846/UC1847

UC3846/UC3847

PARAMETER

TEST CONDITIONS

UC2846/UC2847

MIN. TYP. MAX. MIN. TYP. MAX. UNITS

Reference Section

Output Voltage

TJ=25°C, IO=1mA

5.05

5.10

5

5.15

20

5.00

5.10

5

5.20

20

V

mV

mV/°C

V

Line Regulation

VIN=8V to 40V

Load Regulation

IL=1mA to 10mA

3

15

3

15

Temperature Stability

Total Output Variation

Output Noise Voltage

Long Term Stability

Over Operating Range, (Note 2)

Line, Load, and Temperature (Note 2)

10Hz ≤ f ≤10kHz, TJ=25°C (Note 2)

TJ=125°C, 1000 Hrs. (Note 2)

0.4

5.00

-10

5.20

4.95

-10

5.25

100

5

100

5

µV

mV

mA

Short Circuit Output Current VREF=0V

-45

2

UC1846/7

UC2846/7

UC3846/7

(Unless otherwise stated, these specifications apply for TA=-55°C to +125°C for UC1846/7;

-40°C to +85°C for the UC2846/7; and 0°C to +70°C for the UC3846/7; VIN=15V, RT=10k,

CT=4.7nF, TA=TJ.)

ELECTRICAL

CHARACTERISTICS (cont.)

UC1846/UC1847

UC3846/UC3847

PARAMETER

TEST CONDITIONS

UC2846/UC2847

MIN. TYP. MAX. MIN. TYP. MAX. UNITS

Oscillator Section

Initial Accuracy

TJ=25°C

VIN=8V to 40V

39

43

-1

47

2

39

43

-1

47

2

kHz

%

V

Voltage Stability

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

Input Offset Current

Common Mode Range

Open Loop Voltage Gain

Unity Gain Bandwidth

CMRR

Over Operating Range (Note 2)

-1

3.9

4.35

2.3

3.9

4.35

2.3

2.5

V

Pin 8=0V

V

Pin 8=0V

2.5

1.5

2.5

1.5

V

Sync Voltage=3.9V, Pin 8=0V

1.3

mA

0.5

-0.6

40

5

-1

0.5

-0.6

40

10

-2

mV

µA

nA

V

250

VIN-2V

250

VIN=8V to 40V

0

80

0.7

75

80

2

0

80

0.7

75

80

2

VIN-2V

∆VO=1.2 to 3V, VCM=2V

TJ=25°C (Note 2)

105

1.0

100

105

6

105

1.0

100

105

6

dB

MHz

dB

mA

V

V_CM=0V to 38V, VIN=40V

VIN=8V to 40V

PSRR

Output Sink Current

Output Source Current

VID=-15mV to -5V, VPIN 7=1.2V

VID=15mV to 5V, VPIN 7=2.5V

-0.4

4.3

-0.5

4.6

0.7

-0.4

4.3

-0.5

4.6

0.7

High Level Output Voltage RL=(Pin 7) 15kΩ

Low Level Output Voltage

1

V

Current Sense Amplifier Section

Amplifier Gain

VPIN 3=0V, Pin 1 Open (Notes 3 & 4)

2.5

1.1

2.75

3.0

2.5

1.1

2.75

3.0

V

Maximum Differential Input Pin 1 Open (Note 3)

Signal (VPIN 4-VPIN 3)

Input Offset Voltage

CMRR

RL (Pin 7)=15kW

1.2

5

1.2

5

V

mV

dB

µA

V

VPIN 1=0.5V, Pin 7 Open (Note 3)

VCM=1V to 12V

25

60

83

60

83

PSRR

VIN=8V to 40V

84

Input Bias Current

Input Offset Current

Input Common Mode Range

Delay to Outputs

VPIN 1=0.5V, Pin 7 Open (Note 3)

-2.5

0.08

-10

1

-2.5

0.08

-10

1

0

VIN-3

500

0

VIN-3

500

TJ=25°C, (Note 2)

200

ns

Current Limit Adjust Section

Current Limit Offset

VPIN 3=0V, VPIN 4=0V, Pin 7 Open

(Note 3)

0.45

0.5

-10

0.55

-30

0.45

0.5

-10

0.55

-30

V

Input Bias Current

Shutdown Terminal Section

Threshold Voltage

VPIN 5=VREF, VPIN 6=0V

µA

250

0

350

1.5

400

VIN

250

0

350

1.5

400

VIN

mV

V

Input Voltage Range

Minimum Latching Current (Note 6)

(IPIN 1)

3.0

mA

3

UC1846/7

UC2846/7

UC3846/7

(Unless otherwise stated, these specifications apply for TA=-55°C to +125°C for UC1846/7;

-40°C to +85°C for the UC2846/7; and 0°C to +70°C for the UC3846/7; VIN=15V, RT=10k,

CT=4.7nF, TA=TJ.)

ELECTRICAL

CHARACTERISTICS (cont.)

UC1846/UC1847

UC3846/UC3847

PARAMETER

TEST CONDITIONS

UC2846/UC2847

MIN. TYP. MAX. MIN. TYP. MAX. UNITS

Shutdown Terminal Section (cont.)

Maximum Non-Latching

Current (IPIN 1)

(Note 7)

1.5

0.8

1.5

0.8

mA

ns

Delay to Outputs

TJ=25°C (Note 2)

300

600

300

600

Output Section

Collector-Emitter Voltage

40

V

µA

V

Collector Leakage Current VC=40V (Note 5)

200

0.4

2.1

200

0.4

2.1

Output Low Level

ISINK=20mA

0.1

0.4

0.1

0.4

ISINK=100mA

V

Output High Level

ISOURCE=20mA

13

12

13.5

50

13

12

13.5

50

V

ISOURCE=100mA

V

Rise Time

Fall Time

CL=1nF, TJ=25°C (Note 2)

300

ns

50

Under-Voltage Lockout Section

Start-Up Threshold

7.7

8.0

7.7

8.0

V

Threshold Hysteresis

Total Standby Current

Supply Current

0.75

17

21

17

21

mA

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

Note 3. Parameter measured at trip point of latch with VPIN 5 = VREF, VPIN 6 = 0V.

∆V_{PIN 7}

∆V_{PIN 4}

Note 4. Amplifier gain defined as: G =

;

V_PIN4= 0 to 1.0V

Note 5. Applies to UC1846/UC2846/UC3846 only due to polarity of outputs.

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

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

APPLICATIONS DATA

Oscillator Circuit









ID

3.6

RT (kΩ)





Output deadtime is determined by the external capacitor, CT, according to the formula: τd (µs) =145CT (µf )

.

ID -









ID = Oscillator discharge current at 25°C is typically 7.5.

For large values of RT: τd (µs) ≈145CT (µf ).

2.2

Oscillator frequency is approximated by the formula:fT (kHz) ≈

.

RT (kΩ) •CT (µf )

4

UC1846/7

UC2846/7

UC3846/7

APPLICATIONS DATA (cont.)

Error Amp Gain and Phase vs Frequency

Error Amp Output Configuration

Error Amp Open-Logic D.C. Gain vs Load Resistance

Parallel Operation

5

UC1846/7

UC2846/7

UC3846/7

APPLICATIONS DATA (cont.)

Pulse by Pulse Current Limiting

R2 VREF

−0.5

R1 + R2

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

3RS

Soft Start and Shutdown /Restart Functions

6

UC1846/7

UC2846/7

UC3846/7

APPLICATIONS DATA (cont.)

Current Sense Amp Connection

A small RC filter may be required in some applications to reduce switch transients.

Differential input allows remote, noise free sensing.

UC1846 Open Loop Test Circuit

7

PACKAGE OPTION ADDENDUM

www.ti.com

2-May-2005

PACKAGING INFORMATION

Orderable Device

Status ⁽¹⁾

Package Package

Pins Package Eco Plan ⁽²⁾Lead/Ball Finish MSL Peak Temp ⁽³⁾

Qty

Type

LCCC

CDIP

LCCC

CDIP

LCCC

CDIP

LCCC

SOIC

CDIP

PDIP

PLCC

SOIC

PDIP

SOIC

CDIP

PDIP

PLCC

SOIC

CDIP

PDIP

Drawing

FK

J

5962-86806012A

5962-8680601EA

5962-8680601V2A

5962-8680601VEA

UC1846J

ACTIVE

20

16

20

16

20

16

20

16

20

16

20

16

1

TBD

POST-PLATE Level-NC-NC-NC

A42 SNPB

Call TI

Level-NC-NC-NC

Call TI

ACTIVE

FK

J

ACTIVE

Call TI

ACTIVE

J

A42 SNPB

Call TI

UC1846J/80257

UC1846J/80364

UC1846J/80619

UC1846J883B

UC1846JQMLV

UC1846L883B

UC1846LQMLV

UC1847J

OBSOLETE

ACTIVE

J

Call TI

J

Call TI

J

1

A42 SNPB

Call TI

Level-NC-NC-NC

Call TI

ACTIVE

J

ACTIVE

FK

J

POST-PLATE Level-NC-NC-NC

ACTIVE

Call TI

OBSOLETE

ACTIVE

UC1847J883B

UC1847L

J

FK

DW

J

UC1847L883B

UC2846DW

40

2000

1

CU NIPDAU Level-2-220C-1 YEAR

UC2846DWTR

UC2846J

ACTIVE

A42 SNPB

Level-NC-NC-NC

UC2846N

ACTIVE

N

25

CU NIPDAU Level-NA-NA-NA

UC2846Q

ACTIVE

FN

DW

N

46

Call TI

Level-2-220C-1 YEAR

UC2846QTR

UC2847DW

ACTIVE

1000

40

ACTIVE

CU NIPDAU Level-2-220C-1 YEAR

CU NIPDAU Level-NA-NA-NA

UC2847DWTR

UC2847N

ACTIVE

2000

25

ACTIVE

UC3846DW

ACTIVE

DW

J

40

CU NIPDAU Level-2-220C-1 YEAR

UC3846DWTR

UC3846J

ACTIVE

2000

1

ACTIVE

A42 SNPB

Level-NC-NC-NC

UC3846N

ACTIVE

N

25

CU NIPDAU Level-NA-NA-NA

UC3846Q

ACTIVE

FN

DW

J

46

Call TI

Level-2-220C-1 YEAR

UC3846QTR

UC3847DW

ACTIVE

1000

40

ACTIVE

CU NIPDAU Level-2-220C-1 YEAR

UC3847DWTR

UC3847J

ACTIVE

2000

OBSOLETE

ACTIVE

Call TI

UC3847N

N

25

CU NIPDAU 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.

Addendum-Page 1

PACKAGE OPTION ADDENDUM

www.ti.com

Eco Plan

2-May-2005

(2)

-

The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS

&

no Sb/Br)

-

please check

http://www.ti.com/productcontent for the latest availability information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined.

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 (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame

retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)

(3)

MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder

temperature.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is

provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the

accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take

reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on

incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited

information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI

to Customer on an annual basis.

Addendum-Page 2

IMPORTANT NOTICE

Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications,

enhancements, improvements, and other changes to its products and services at any time and to discontinue

any product or service without notice. Customers should obtain the latest relevant information before placing

orders and should verify that such information is current and complete. All products are sold subject to TI’s terms

and conditions of sale supplied at the time of order acknowledgment.

TI warrants performance of its hardware products to the specifications applicable at the time of sale in

accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI

deems necessary to support this warranty. Except where mandated by government requirements, testing of all

parameters of each product is not necessarily performed.

TI assumes no liability for applications assistance or customer product design. Customers are responsible for

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solutions:

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amplifier.ti.com

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dsp.ti.com

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Digital Control

Military

www.ti.com/broadband

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interface.ti.com

logic.ti.com

Power Mgmt

Microcontrollers

power.ti.com

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microcontroller.ti.com

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www.ti.com/wireless

Mailing Address:

Texas Instruments

Post Office Box 655303 Dallas, Texas 75265


型号：	UC2847L
厂家：	TEXAS INSTRUMENTS
描述：	0.5A SWITCHING CONTROLLER, 500kHz SWITCHING FREQ-MAX, CQCC20, CERAMIC, LCC-20 控制器
文件：	总10页 (文件大小：644K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

UC2847L [TI]

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