The AP3842/3/4/5 family of control ICs provides the
necessary features to implement off-line or DC to
DC fixed frequency current mode control schemes
with a minimal external parts count. Internally
implemented circuits include under voltage lockout
featuring start-up current less than 0.5 mA, a
precision reference trimmed for accuracy at the
error amp input, logic to insure latched operation, a
PWM comparator which also provides current limit
control, and a totem pole output stage designed to
source or sink high peak current. The output stage,
suitable for driving N-Channel MOSFETs, is low in
the off-state.
Differences between members of this family are the
under-voltage lockout thresholds and maximum
duty cycle ranges. The AP3842 and AP3844 have
UVLO thresholds of 16V(on) and 10V(off), ideally
suited for off-line applications. The corresponding
thresholds for the AP3843 and AP3845 are 8.5V
and 7.6V. The AP3842 and AP3843 can operate to
duty cycles approaching 100%. A range of the zero
to < 50% is obtained by the AP3844 and AP3845
by the addition of an internal toggle flip flop which
blanks the output off every other clock cycle.
Optimized for Off-Line and DC to DC Converters
Low Start-Up Current (≦0.5mA)
Automatic Feed Forward Compensation
Pulse-by-Pulse Current Limiting
Enhanced Load Response Characteristics
Under-Voltage Lockout (UVLO) with Hysteresis
Double Pulse Suppression
High Current Totem Pole Output
Internally Trimmed Bandgap Reference
Current Mode Operation to 500KHZ
Low Ro Error Amplifier
Pin Connections
PDIP-8L, SOP-8L
Top View
COMP.
V
FB
I
SENSE
R
T
/C
T
1
2
3
4
8
7
6
5
V
REF
V
I
OUTPUT
GROUND
Ordering Information
AP 384X X X X
Part No.
2:3842
3:3843
4:3844
5:3845
Package
S8:SOP-8L
N8:PDIP-8L
Lead Free
Packing
Blank: Tube
Blank : Normal
L : Lead Free Package A : Taping
This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of
this product. No rights under any patent accompany the sale of the product.
Rev.1.0 Oct.11, 2004
1/8
AP3842/3/4/5
High Performance Current Mode PWM Controller
Block Diagram
( toggle flip flop used only in AP3844 and AP3845 )
Vi
7
36V
GROUND
5
16V
UVLO
8
INTERNAL
BIAS
5V
S/R
REF
VREF
5V 50mA
2.50V
VREF GOOD
LOGIC
T
2R
R
S
R
1V
CURRENT
SENSE
COMPARATOR
PWM
LATCH
6
RT/CT
4
OUTPUT
OSC.
ERROR AMP.
2
VFB
COMP
CURRENT
SENSE
1
3
AP384X
Absolute Maximum Ratings
Symbol
V
i
V
i
I
o
E
o
P
tot
P
tot
T
stg
T
L
Parameter
Supply Voltage (low impedance source)
Supply Voltage (li < 30mA)
Output Current
Output Energy (capacitive load)
Analog Inputs (pins2,3)
Error Amplifier Output Sink Current
Power Dissipation at T
amb
≦50
0
C (PDIP8)
Power Dissipation at T
amb
≦25
0
C (SOP8)
Storage Temperature Range
Lead Temperature (soldering 10s)
Value
36
Self Limiting
±0.7
5
-0.3 to 5.5
10
1.25
800
-65 to 150
260
Unit
V
A
µJ
V
mA
W
mW
o
C
o
C
*Notes: 1. All voltages are with respect to pin 5, all currents are positive into the specified terminal.
Electrical Characteristics
(Unless otherwise stated, these specifications apply for
0≦T
amb
≦70
C for AP384X ; V
i
= 15V(note 5); R
T
= 10KΩ;C
T
= 3.3nF)
o
Symbol
Parameter
Test Conditions
AP384X
Min. Typ. Max.
Unit
REFERENCE SECTION
V
REF
Output Voltage
∆V
REF
Line Regulation
∆V
REF
Load Regulation
∆V
REF/
∆T
Temperature Stability
Total Output Variation
e
N
I
SC
Tj = 25
0
C I
0
=1mA
4.90 5.00 5.10
V
12V≦V
i
≦25V
2
20
mV
1mA≦I
o
≦20mA
3
25
mV
(Notes 2)
0.2 0.4 mV/
0
C
Line, Load, Temperature (Notes 2) 4.82
5.18
V
0
10Hz≦f≦10KHz Tj=25 C (Notes
50
µV
Output Noise Voltage
2)
0
Long Term Stability
T
amb
=125 C, 1000Hrs (Notes 2)
5
25
mV
Output Short Circuit current
-85 -120 mA
Anachip Corp.
www.anachip.com.tw
2/8
Rev.1.0 Oct.11, 2004
AP3842/3/4/5
High Performance Current Mode PWM Controller
Electrical Characteristics(Continued)
(Unless otherwise stated, these specifications apply for
0≦T
amb
≦70
C for AP384X ; V
i
= 15V(note 5); R
T
= 10KΩ;C
T
= 3.3nF)
o
Symbol
Parameter
Test Conditions
Tj=25
0
C (Notes 6, 7)
12V≦V
i
≦25V
T
MIN
≦T
amb
≦T
MAX
(Notes 2)
V
PIN4
Peak to Peak
0
Tj=25 C V
PIN4
=2V
V
PIN1
=2.5V
V
FB
=5V
0V≦V
0
≦4V
Tj=25
o
C
12V≦V
i
≦25V
V
PIN2
=2.7V V
PIN1
=1.1V
V
PIN2
=2.3V V
PIN1
=5V
V
PIN2
=2.3V; R
L
=15KΩ to ground
V
PIN2
=2.7V; R
L
=15KΩ to pin 8
(Notes3&Notes4)
V
PIN1
=5V (Notes3)
12≦V
i
≦25V
(Notes3)
AP384X
Min. Typ. Max.
49
52
0.2
0.5
1.6
8.3
55
1
Unit
KHz
%
%
V
mA
V
µA
dB
MHz
dB
mA
mA
V
V
V/V
V
dB
µA
ns
V
V
V
V
ns
ns
V
V
V
V
V
%
%
%
mA
mA
V
OSCILLATOR SECTION
f
s
Oscillator Frequency
Voltage Stability
Temperature Stability
V
4
Amplitude
Discharge Current
ERROR AMP SECTION
V
2
Feedback Input Voltage
I
b
Input Bias Current
A
VOL
B
Unity Gain Bandwidth
Supply Voltage Rejection
SVRR
Ratio
I
O
Output Sink Current
I
O
Output Source Current
V
OUT
High
V
OUT
Low
CURRENT SENSE SECTION
G
v
Gain
V
3
Maximum Input Signal
Supply Voltage Rejection
SVRR
Ratio
I
b
Input Bias Current
Delay to Output
OUTPUT SECTION
V
OL
V
OH
Output Low Level
Output High Level
7.8
8.8
2.42 2.50 2.58
-0.1
-2
65
90
0.7
1
60
2
-0.5
5
70
6
-0.8
7
0.8
3
1
70
-2
150
-10
300
0.4
2.2
1.1
3.15
1.1
2.85
0.9
T
r
Rise Time
T
f
Fall Time
V
OLS
UVLO Saturation
UNDER-VOLTAGE LOCKOUT SECTION
Start Threshold
Min Operating Voltage After
Turn-on
PWM SECTION
Maximum Duty Cycle
Minimum Duty Cycle
TOTAL STANDBY CURRENT
I
st
I
i
V
iz
Start-up Current
Operating Supply Current
Zener Voltage
I
SINK
= 20mA
I
SINK
= 200mA
I
SOURCE
= 20mA
I
SOURCE
= 200mA
Tj=25
0
C C
L
=1nF (Notes2)
Tj=25
0
C C
L
=1nF (Notes2)
Vcc = 6V ; Isink = 1mA
3842/4
3843/5
3842/4
3843/5
3842/3
3844/5
13
12
0.1
1.6
13.5
13.5
50
50
0.1
16
8.4
10
7.6
96
48
150
150
1.1
17.5
9
11.5
8.2
14.5
7.8
8.5
7.0
94
47
50
0
0.5
17
Vi=14V,3842/4 ;
Vi=6.5V 3843/5
V
PIN2
=V
PIN3
=0V
I
i
=25mA
0.3
30
12
36
Anachip Corp.
www.anachip.com.tw
3/8
Rev.1.0 Oct.11, 2004
AP3842/3/4/5
High Performance Current Mode PWM Controller
Notes：2.These parameters, although guaranteed, are not 100% tested in production.
3.Parameter measured at trip point of latch with V
PIN2
=0.
4.Gain defined as:
∆V
PIN1
; 0≦V
PIN3
≦0.8V
A=
∆V
PIN3
5.Adjust V
i
above the start threshold before setting at 15V.
6.Output frequency equals oscillator frequency for the AP3842 and AP3843.
7.Output frequency is one and half oscillator frequency for the AP3844 and AP3845.
Figure 1 : Error Amp Configuration.
2.5V
0.8 mA
Zf
Zf
2
COMP
1
V
FB
Error amp can source or sink up to 0.5mA
Figure 2 : Under Voltage Lockout.
ON/OFF COMMAND
TO REST OF IC
I
CC
V
i
7
AP3842 AP3843
AP3844 AP3845
V
<17 mA
ON
16V
10V
8.4V
7.6V
<1 mA
V
V
OFF
OFF
V
V
CC
ON
During Under-Voltage Lockout, the output driver is biased to sink minor amounts of current. Pin 6 should be
shunted to ground with a bleeder resistor to prevent activating the power switch with extraneous leakage
currents.
Figure 3 : Current Sense Circuit.
ERROR
AMP
I
S
2R
COMP
R
C
3
1
CURRENT
SENSE
R
1V
CURRENT
SENSE
COMPARATOR
Rs
5
GND
Anachip Corp.
www.anachip.com.tw
4/8
Rev.1.0 Oct.11, 2004
AP3842/3/4/5
High Performance Current Mode PWM Controller
Peak current(i
s
) is determined by the formula
1.0V
I
S
max
≈
R
S
A small RC filter may be required to suppress switch transients.
Figure 4.
V
REF
R
T
/C
T
GROUND
8
R
T
4
C
T
5
for R
T
> 5KΩ f=
1.72
R
T
C
T
Figure 5 : Open Loop Test Circuit.
V
REF
R
T
A
1
COMP.
V
FB
V
REF
4.7K
2N2222
8
7
6
5
0.1
uF
Vi
100K
ERROR AMP.
ADJUST
2
1K
I
SENSE
V
i
5K
AP3842
3
4
I
SENSE
ADJUST
4.7K
OUTPUT
0.1
uF
TW
1K
OUTPUT
R
T/
C
T
GROUND
C
GROUND
T
High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and
bypass apacitors should be connected close to pin 5 in a single point ground. The transistor and 5 KΩ
potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3.
Dear experts, I am now learning PIC18 series microcontrollers. The integrated development environment I installed is MPLAB IDE v8.89, and the C language compiler is the genuine MCC18_V3.00. It seems t...
The previous post introduced the interface design and implemented the interface test through software simulation, which basically met expectations. This post introduces adding hardware support and imp...
When we want to perform both modulus and quotient operations on a number, we can express it like this in KEIL C: [code] unsigned int i,j,k; i=k%15; j=k/15; [/code] Then I looked at the assembly code g...
If a digital multimeter uses a 1.5V battery to replace a 9V laminated battery through boosting, a power switch must usually be installed separately. This brings inconvenience to production and use. Th...
1. Test conditions Hardware: STM32L432KC Main frequency: 80MHz Compiler: IAR 8.20.1 Compiler options: High Speed no size constraints CRC generator polynomial: 0x782f 2. Test Method The softwar...[Details]
After we understand the use of libopencm3, we find that libopencm3 is only suitable for small projects. Its biggest feature is the convenience of USB. So when we configure large projects, is there a ...[Details]
stm32cubeMX graphical configuration content STM32CubeMX is part of the original STMCube initiative from st microelectronics, and STM32Cube includes STM32CubeMX. STM32CubeMX is a graphical software co...[Details]
Overview
Lightning is a strong discharge phenomenon that occurs between thunderstorm clouds and between thunderstorm clouds and the earth due to severe convective weather. Lightning is gen...[Details]
The Wassenaar Arrangement, everything started during the Cold War. Let's learn more about it with the embedded editor.
background
After the end of World War II, the United States ...[Details]
ZTE was punished, and Hou Weigui, who had already retired, had to come out of retirement again and run around to mediate. Let's follow the embedded editor to learn about the relevant content.
...[Details]
China Energy Storage Network:
At the Boao Forum, Zhu Min, the current dean of the National Institute of Finance at Tsinghua University, said: "When talking about blockchain, we must first sep...[Details]
In the Chinese automobile market, the trend of new energy vehicles and driverless cars is leading the transformation of China's automobile industry. As the world's largest automobile market, "Chinese...[Details]
The application of millimeter wave technology in mobile communications also involves a series of technical problems, including the large propagation loss of millimeter waves and the susceptibility ...[Details]
The photovoltaic inverter is the core equipment of the photovoltaic system. Its main function is to convert the direct current generated by the photovoltaic modules into alternating current that meets...[Details]
Different from 51, AVR and other single-chip microcomputers, the clock signal sources of msp430 include LFXT1, XT2 and DCO. 1. LFXT1: It can connect high-speed and low-speed crystal oscillators. In l...[Details]
1. FSMC Brief FSMC, the Flexible Static Storage Controller, is capable of interfacing with synchronous or asynchronous memories and 16-bit PC memory cards. The FSMC interface of STM32 s...[Details]
Temperature, humidity and irradiance are must-measure items in the photovoltaic industry. However, most of the current data collection is done by storing data in USB flash drives for offline analys...[Details]
As shown in the figure, the author soldered a STM32F207VET6 board using a TQFP (32-100PIN) 0.55MM to direct plug adapter board. The board leads out the SWD debug interface (only PA13 and PA14 are occ...[Details]
Microchip MCU
京公网安备 11010802033920号
EEWORLD
