UC3843A现货热卖使用介绍供应商报价哪里找芯片批发报价-中国IC网-芯三七

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产品型号UC3843A的概述

UC3843A芯片概述 UC3843A是一款电子控制器，广泛应用于开关电源、稳压电源和其他电力转换系统中。这款芯片由Unitrode公司开发，现为Texas Instruments的一部分。UC3843A通常用于高频开关电源和相应的DC-DC转换器，其设计目标是实现高效率、低噪声和良好的负载响应能力。 UC3843A采用电流模式控制的方法，使其在动态负载条件下能够快速响应，这为高频开关操作提供了可靠的解决方案。该芯片支持多种主电路架构，包括正增益和负增益结构。集成在芯片内部的调制电路及保护功能，使得UC3843A在设计、实现和应用方面具有广泛的灵活性。 UC3843A的详细参数 UC3843A的主要技术参数包括： - 工作电压范围：8 V至35 V - 启动电流：未加负载时，初始启动电流为约30 μA - 阈值电压：典型值为5 V，具备稳定的参考电压 - 输出能力：推挽式输出，可驱动外...

产品型号UC3843A的Datasheet PDF文件预览

LIN DOC #: 1840

UC184xA/284xA/384xA

C U R R E N T M O D E P W M C O N T R O L L E R

P R O D U C T I O N D A T A S H E E T

T H E I N F I N I T E P O W E R O F I N N O V A T I O N

DESCRIPTION

KEY FEATURES

■ LOW START-UP CURRENT. (0.5mA max.)

■ TRIMMED OSCILLATOR DISCHARGE

The UC184xA family of control ICs

provides all the necessary features to

implement off-line fixed-frequency,

current-mode switching power supplies

with a minimum of external compo-

nents. The current mode architecture

demonstrates improved load regulation,

pulse-by-pulse current limiting and

inherent protection of the power supply

output switch. The IC includes: A

bandgap reference trimmed to ±1%

accuracy, an error amplifier, a current

sense comparator with internal clamp to

1V, a high current totem pole output

stage for fast switching of power

MOSFET's, and an externally program-

mable oscillator to set frequency and

CURRENT. (See Product Highlight)

maximum duty cycle. The under-

voltage lock-out is designed to operate

with 250µA typ. start-up current,

allowing an efficient bootstrap supply

voltage design. Available options for

this family of products, such as start-up

voltage hysteresis and duty cycle, are

summarized below in the Available

Options section. The UC184xA family

of control ICs is also available in 14-pin

SOIC package which makes the Power

Output Stage Collector and Ground pins

available.

p OPTIMIZED FOR OFF-LINE AND DC-TO-DC

CONVERTERS.

p AUTOMATIC FEED FORWARD

COMPENSATION.

p PULSE-BY-PULSE CURRENT LIMITING.

p ENHANCED LOAD RESPONSE

CHARACTERISTICS.

p UNDER-VOLTAGE LOCKOUT WITH

HYSTERESIS.

p DOUBLE PULSE SUPPRESSION.

p HIGH-CURRENT TOTEM POLE OUTPUT.

p INTERNALLY TRIMMED BANDGAP

REFERENCE.

p 500KHz OPERATION.

PRODUCT HIGHLIGHT

p LOW R_OERROR AMPLIFIER.

COMPARISON OF UC384XA VS. SG384X DISCHARGE CURRENT

APPLICATIONS

UC384xA

■ ECONOMICAL OFF-LINE FLYBACK OR

SG384x

Min. Limit

Max. Limit

FORWARD CONVERTERS.

T_A=25°C

■ DC-DC BUCK OR BOOST CONVERTERS.

■ LOW COST DC MOTOR CONTROL.

A V A

O P

T I O N S

Part #

Start-Up Hysteresis Max. Duty

Voltage

16V

Cycle

<100%

<50%

UCx842A

0.8V

UCx843A 8.4V

UCx844A 16V

UCx845A 8.4V

7.5

7.8

−3σ

8.3

Mean

8.8

+3σ

9.3

0.8V

Discharge Current Distribution - mA

PACKAGE ORDER INFORMATION

Plastic DIP

8-pin

Plastic SOIC

8-pin

Plastic SOIC

14-pin

Ceramic DIP

8-pin

T_A(°C)

0 to 70

-40 to 85

-55 to 125

UC384xAM

UC284xAM

—

UC384xADM

UC284xADM

—

UC384xAD

UC284xAD

—

UC284xAY

UC184xAY

Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (i.e. UC3842ADMT)

F O R F U R T H E R I N F O R M AT I O N C A L L ( 7 1 4 ) 8 9 8 - 8 1 2 1

Rev. 1.2 12/95

11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

UC184xA/284xA/384xA

C U R R E N T M O D E P W M C O N T R O L L E R

P R O D U C T I O N D A T A S H E E T

ABSOLUTE MAXIMUM RATINGS (Note 1)

PACKAGE PIN OUTS

Supply Voltage (Low Impedance Source) (V_CC) ......................................................... 30V

Supply Voltage (I_CC< 30mA).......................................................................... Self Limiting

Output Current............................................................................................................. ±1A

Output Energy (Capacitive Load)................................................................................. 5µJ

Analog Inputs (V_FB& I_SENSE) ........................................................................ -0.3V to +6.3V

Error Amp Output Sink Current ............................................................................... 10mA

Power Dissipation at T_A= 25°C (M Package).............................................................. 1W

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

Lead Temperature (Soldering, 10 Seconds)............................................................. 300°C

COMP

V_FB

I_SENSE

R_T/C_T

V_REF

V_CC

OUTPUT

GND

M & Y PACKAGE

(Top View)

COMP

V_FB

I_SENSE

R_T/C_T

V_REF

V_CC

OUTPUT

GND

Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect

to Ground. Currents are positive into, negative out of the specified terminal. Pin

numbers refer to DIL packages only.

DM PACKAGE

(Top View)

THERMAL DATA

M PACKAGE:

THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ_JA

DM PACKAGE:

95°C/W

165°C/W

120°C/W

130°C/W

COMP

N.C.

V_FB

N.C.

I_SENSE

N.C.

R_T/C_T

V_REF

N.C.

V_CC

V_C

OUTPUT

GND

PWR GND

THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ_JA

D PACKAGE:

THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ_JA

Y PACKAGE:

D PACKAGE

(Top View)

THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ_JA

Junction Temperature Calculation: T_J= T_A+ (P_Dx θ_JA).

The θ numbers are guidelines for the thermal performance of the device/pc-board system.

All of^Jt^Ahe above assume no ambient airflow

Rev. 1.2 12/95

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

UC184xA/284xA/384xA

C U R R E N T M O D E P W M C O N T R O L L E R

P R O D U C T I O N D A T A S H E E T

ELECTRICAL CHARACTERISTICS

(Unless otherwise specified, these specifications apply over the operating ambient temperatures for UC384xA with 0°C ≤ T_A≤ 70°C, UC284xA with -40°C ≤ T_A≤ 85°C,

UC184xA with -55°C ≤ T_A≤ 125°C; V_CC=15V; R_T=10K; C_T=3.3nF. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal

to the ambient temperature.)

UC184xA/284xA

Min. Typ. Max. Min. Typ. Max.

UC384xA

Parameter

Symbol

Test Conditions

Units

Reference Section

Output Voltage

V_REF

T_J= 25°C, I_L= 1mA

4.95 5.00 5.05 4.90 5.00 5.10

Line Regulation

12 ≤ V_IN≤ 25V

1 ≤ I_O≤ 20mA

Load Regulation

0.2 0.4

5.1 4.82

0.2 0.4 mV/°C

Temperature Stability (Note 2 & 7)

Total Output Variation

Output Noise Voltage (Note 2)

Long Term Stability (Note 2)

Output Short Circuit Current

Oscillator Section

4.9

5.18

Over Line, Load, and Temperature

10Hz ≤ f ≤ 10kHz, T_J= 25°C

T_A= 125°C, t = 1000hrs

µV

V_N

I_SC

-30 -100 -180 -30 -100 -180

Initial Accuracy (Note 6)

Voltage Stability

T_J= 25°C

12 ≤ V_CC≤ 25V

0.2

kHz

Temperature Stability (Note 2)

Amplitude (Note 2)

Discharge Current

T_MIN≤ T_A≤ T_MAX

1.7

7.8 8.3 8.8 7.8 8.3 8.8

7.5 8.8 7.6 8.8

T_J= 25°C, V_{PIN 4}= 2V

V_{PIN 4}= 2V, T_MIN≤ T_A≤ T_MAX

Error Amp Section

Input Voltage

Input Bias Current

V_{PIN 1}= 2.5V

2.45 2.50 2.55 2.42 2.50 2.58

µA

MHz

I_B

-0.3

-1

-0.3

-2

Open Loop Gain

A_VOL

2 ≤ V_O≤ 4V

0.7

Unity Gain Bandwidth (Note 2)

Power Supply Rejection Ratio (Note 3)

Output Sink Current

Output Source Current

Output Voltage High Level

Output Voltage Low Level

Current Sense Section

UGBW T_j= 25°C

PSRR

I_OL

I_OH

12 ≤ V_CC≤ 25V

V_{PIN 2}= 2.7V, V_{PIN 1}= 1.1V

V_{PIN 2}= 2.3V, V_{PIN 1}= 5V

-0.5 -0.8

V_OH

V_OL

V_{PIN 2}= 2.3V, R_L= 15K to ground

V_{PIN 2}= 2.7V, R_L= 15K to V_REF

0.7 1.1

Gain (Note 3 & 4)

A_VOL

2.85

0.9

-2

3.15 2.85

1.1 0.9

-2

3.15

1.1

V/V

µA

Maximum Input Signal (Note 3)

Power Supply Rejection Ratio (Note 3)

Input Bias Current

V_{PIN 1}= 5V

PSRR

I_B

12 ≤ V_CC≤ 25V

-10

150 300

Delay to Output (Note 2)

Output Section

T_pd

V_{PIN 3}= 0 to 2V

Output Low Level

I_SINK= 20mA

I_SINK= 200mA

0.1 0.4

1.5 2.2

0.1 0.4

1.5 2.2

V_OL

Output High Level

I_SOURCE= 20mA

13 13.5

12 13.5

13 13.5

12 13.5

50 150

V_OH

I_SOURCE= 200mA

T_J= 25°C, C_L= 1nF

V_CC= 5V, I_SINK= 10mA

Rise Time (Note 2)

Fall Time (Note 2)

UVLO Saturation

T_R

T_F

V_SAT

50 150

0.7 1.2

50 150

0.7 1.2

(Electrical Characteristics continue next page.)

Rev. 1.2 12/95

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

UC184xA/284xA/384xA

C U R R E N T M O D E P W M C O N T R O L L E R

P R O D U C T I O N D A T A S H E E T

ELECTRICAL CHARACTERISTICS (Con't.)

UC184xA/284xA

Min. Typ. Max. Min. Typ. Max.

UC384xA

Parameter

Symbol

Test Conditions

Units

Under-Voltage Lockout Section

Start Threshold

x842A/4A

x843A/5A

x842A/4A

x843A/5A

7.8 8.4 9.0 7.8 8.4 9.0

10 11 8.5 10 11.5

7.0 7.6 8.2 7.0 7.6 8.2

17 14.5 16 17.5

Min. Operation Voltage After Turn-On

PWM Section

Maximum Duty Cycle

x842A/3A

x844A/5A

96 100 94

96 100

Minimum Duty Cycle

Total Standby Section

Start-Up Current

0.3 0.5

Operating Supply Current

Zener Voltage

I_CC

V_Z

I_CC= 25mA

Notes: 2. These parameters, although guaranteed, are not 100% tested in

production.

7. "Temperature stability, sometimes referred to as average temperature

coefficient, is described by the equation:

3. Parameter measured at trip point of latch with V_VFB= 0.

V_REF(max.) - V_REF(min.)

Temp Stability =

∆ V_COMP

T_J(max.) - T (min.)

4. Gain defined as: A_VOL

; 0 ≤ V_ISENSE≤ 0.8V.

∆ V_ISENSE

V_REF(max.) & V_REF(min.) are the maximum & minimum reference

voltage measured over the appropriate temperature range. Note that

the extremes in voltage do not necessarily occur at the extremes in

temperature."

5. Adjust V_CCabove the start threshold before setting at 15V.

6. Output frequency equals oscillator frequency for the UC1842A

and UC1843A. Output frequency is one half oscillator frequency

for the UC1844A and UC1845A.

BLOCK DIAGRAM

V_CC

34V

UVLO

V_REF

5.0V

50mA

Ref

S / R

Hysteresis

6V (1842A/4A)

0.8V (1843A/5A)

GROUND

UVLO

16V (1842A/4A)

8.4V (1843A/5A)

Internal

Bias

2.5V

V_C

V_REF

Good Logic

R_T/C_T

Oscillator

***

OUTPUT

Error Amp

V_FB

PWM

Latch

POWER GROUND

Current Sense

Comparator

COMP

CURRENT SENSE

- V_CCand V_Care internally connected for 8 pin packages.

- POWER GROUND and GROUND are internally connected for 8 pin packages.

- Toggle flip flop used only in x844A and x845A series.

***

Rev. 1.2 12/95

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

UC184xA/284xA/384xA

C U R R E N T M O D E P W M C O N T R O L L E R

P R O D U C T I O N D A T A S H E E T

CHARACTERISTIC CURVES

FIGURE 1. — OSCILLATOR FREQUENCY vs. TIMING

RESISTOR

V_REF

C_T= 1nF

R_T

R_T/C_T

C_T= 2.2nF

C_T

100k

GROUND

C_T= 4.7nF

10k

1.72

R_TC_T

For R_T> 5k, f »

Note: Output drive frequency is half the oscillator frequency for

the UCx844A/5A devices.

300

1.0k

3.0k

10.0k

30.0k

100k

R_T- (ohms)

FIGURE 2. — MAXIMUM DUTY CYCLE vs. TIMING RESISTOR

100.0

80.0

60.0

40.0

20.0

300

1.0k

3.0k

10.0k

30.0k

100k

R_T- (ohms)

Rev. 1.2 12/95

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

UC184xA/284xA/384xA

C U R R E N T M O D E P W M C O N T R O L L E R

P R O D U C T I O N D A T A S H E E T

TYPICAL APPLICATION CIRCUITS

FIGURE 4. — MOSFET PARASITIC OSCILLATIONS

FIGURE 3. — CURRENT SENSE SPIKE SUPPRESSION

V_CCDC BUS

V_CC

DC BUS

R_S

R₁

UCx84xA

I_PK

CHANGE

1.0V

R_S

I_PK(MAX)

R_S

The RC low pass filter will eliminate the leading edge current spike

caused by parasitics of Power MOSFET.

A resistor (R₁) in series with the MOSFET gate will reduce overshoot

& ringing caused by the MOSFET input capacitance and any

inductance in series with the gate drive. (Note: It is very important to

have a low inductance ground path to insure correct operation of the

I.C. This can be done by making the ground paths as short and as

wide as possible.)

FIGURE 5. — EXTERNAL DUTY CYCLE CLAMP AND MULTI-UNIT SYNCHRONIZATION

R_A

R_B

UCx84xA

555

TIMER

0.01

To other

UCx84xA devices

1.44

f =

(R_A+ 2R_B)C

R_B

Precision duty cycle limiting as well as synchronizing several parts is

possible with the above circuitry.

R_A+ 2R_B

Rev. 1.2 12/95

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

UC184xA/284xA/384xA

C U R R E N T M O D E P W M C O N T R O L L E R

P R O D U C T I O N D A T A S H E E T

TYPICAL APPLICATION CIRCUITS (continued)

FIGURE 6. — SLOPE COMPENSATION

V_CC

DC BUS

UCx84xA

7(12)

V_O

8(14)

R_T

UVLO

REF

INTERNAL

BIAS

2.5V

2N222A

V_REF

GOOD LOGIC

7(11)

6(10)

R_SLOPE

4(7)

OSCILLATOR

From V_O

C_T

C.S.

COMP

R_i

2(3)

R_F

ERROR

AMP

5(8)

3(5)

PWM

LATCH

R_d

C_F

1(1)

R_S

5(9)

Due to inherent instability of current mode converters running above 50% duty cycle, slope compensation should be added to either

the current sense pin or the error amplifier. Figure 6 shows a typical slope compensation technique.

FIGURE 7. — OPEN LOOP LABORATORY FIXTURE

V_REF

R_T

V_CC

UCx84xA

2N2222

100K

4.7K

COMP

V_REF

V_FB

V_CC

0.1µF

ERROR AMP

ADJUST

I_SENSE

ADJUST

OUTPUT

4.7K

I_SENSE

OUTPUT

GROUND

R_TC_T

GROUND

C_T

High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should be

connected to pin 5 in a single point ground. The transistor and 5k potentiometer are used to sample the oscillator waveform and apply an

adjustable ramp to pin 3.

Rev. 1.2 12/95

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

UC184xA/284xA/384xA

C U R R E N T M O D E P W M C O N T R O L L E R

P R O D U C T I O N D A T A S H E E T

TYPICAL APPLICATION CIRCUITS (continued)

FIGURE 8. — OFF-LINE FLYBACK REGULATOR

MBR735

4.7kW 1W

220µF

250V

4.7kW

3600pF

400V

1N4004

2-5A

4700µF

10V

140kW

1/2W

1N4935

INPUT

1N4004

1N4935

16V

10µF

20V

20kW

UC3844A

820pF

0.01µF

V_FB

V_CC

2.5kW

27kW

150kW

COMP

OUT

3.6kW

100pF

V_REF

1kW

470pF

CUR

SEN

10kW

0.85kW

R_T/C_T

GND

0.01µF

.0022µF

ISOLATION

BOUNDARY

SPECIFICATIONS

Input line voltage:

Input frequency:

Switching frequency:

Output power:

Output voltage:

Output current:

Line regulation:

Load regulation:

Efficiency @ 25 Watts,

V_IN= 90VAC:

90VAC to 130VAC

50 or 60Hz

40KHz 10%

25W maximum

5V +5%

2 to 5A

0.01%/V

8%/A*

* This circuit uses a low-cost feedback scheme in which the DC

voltage developed from the primary-side control winding is

sensed by the UC3844A error amplifier. Load regulation is

therefore dependent on the coupling between secondary and

control windings, and on transformer leakage inductance.

70%

V_IN= 130VAC:

65%

Output short-circuit current:

2.5Amp average

Rev. 1.2 12/95

UC3843A相关文章

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UC3843A-D08-T产品参数

型号:	UC3843A-D08-T
生命周期：	Active
IHS 制造商：	UNISONIC TECHNOLOGIES CO LTD
零件包装代码：	DIP
包装说明：	DIP-8
针数：	8
Reach Compliance Code：	compliant
ECCN代码：	EAR99
HTS代码：	8542.39.00.01
风险等级：	5.64
Is Samacsys：	N
模拟集成电路 - 其他类型：	SWITCHING CONTROLLER
控制模式：	CURRENT-MODE
控制技术：	PULSE WIDTH MODULATION
最大输入电压：	25 V
最小输入电压：	8.2 V
标称输入电压：	15 V
JESD-30 代码：	R-XDIP-T8
JESD-609代码：	e0
长度：	9.2 mm
功能数量：	1
端子数量：	8
最高工作温度：	70 °C
最低工作温度：
最大输出电流：	1 A
封装主体材料：	UNSPECIFIED
封装代码：	DIP
封装形状：	RECTANGULAR
封装形式：	IN-LINE
认证状态：	Not Qualified
座面最大高度：	4.31 mm
表面贴装：	NO
切换器配置：	SINGLE
最大切换频率：	500 kHz
温度等级：	COMMERCIAL
端子面层：	TIN LEAD
端子形式：	THROUGH-HOLE
端子节距：	2.54 mm
端子位置：	DUAL
宽度：	7.62 mm
Base Number Matches：	1

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