AP3039 is a current mode high voltage low-side Nchannel MOSFET controller which is ideal for boost
regulators. It contains all the features needed to implement single ended primary topology DC/DC
converters.
The input voltage range of AP3039 is from 5V to 27V.
Its operation frequency is adjustable from 150kHz to
1MHz.
The AP3039 has UVLO (Under Voltage Lock Out)
circuit. It uses two external resistors to set the UVLO
voltage. The AP3039 also has an over output voltage
protection to limit the output voltage. The OVP voltage can be set through external resistors. If the output
voltage is higher than the OVP high threshold point, it
will disable the driver, when the output voltage drops
to the OVP low threshold point, it will enable the
driver. It also features a soft start to reduce the inrush
current when power on, the soft start time can be set
through an external capacitor.
Features
·Input Voltage Range 5V to 27V
·0.6A Peak MOSFET Gate Driver
·20ns Quick MOSFET Gate Driver
·Duty Cycle Limit of 90%
·Programmable UVLO
·Programmable Over Voltage Protection
·Cycle by Cycle Current Limit
·Adjustable Soft-Start
·Adjustable Operation Frequency from 150kHz to
1MHz
Applications
·LED Lighting
·Notebook
·LCD Display Modules
The AP3039 is available in QFN-3x3-16 and SOIC-14
packages.
78RTAn external resistor connected from this pin to GND to set the operating frequency
89CSSense switch current pin, which is used for current mode control and for current limit
910AGNDReference ground
1011SHDN
1112FBVoltage Feedback Pin. The reference voltage is 500mV
1313COMPCompensation Pin. This pin is the output of the internal Error Amplifier
1414SS
No connection (for
6V linear regulator output pin. VCC is used to bias the gate driver for the external
MOSFET. If V
bypass switch. If V
GND (recommend to connect with AGND pin) with a ceramic capacitor
Connect this pin to the gate of external MOSFET, the gate driver has 0.6A peak current
capability
This pin can be connected to current matched chip and receives error signal used to shut
down the system
An external soft start time capacitor is connected from this pin to ground and is charged by
internal 12µA current source to control regulator soft start time
QFN-3x3-16 package only)
is less than 8.5V, the VCC is equal to VIN minus drop voltage across
IN
is less than 6V, connect VCC to VIN. This pin should be bypassed to
IN
151UVLO
162OVOver output voltage protection pin
EP
Two resistors connected from this pin to ground and the VIN pin respectively to set start up
and shutdown level
Exposed backside pad. Solder to the circuit board ground plane with sufficient copper
connection to ensure low thermal resistance (for
Thermal Resistance (Junction to Ambient, no Heat sink) θ
Operating Junction TemperatureT
Storage Temperature RangeT
Lead Temperature (Soldering, 10sec)T
IN
CC
OUT
FB
UVLO
CS
SHDN
EN
OV
JA
J
STG
LEAD
QFN-3x3-16
SOIC-14102
30V
10V
10V
7V
7V
7V
7V
V
IN
7V
60
o
C/W
150
-65 to 150
260
ESD (Machine Model)200V
V
o
C
o
C
o
C
ESD (Human Body Model)2000V
Note 1: Stresses greater than those listed under "Absolute Maximum Ratings" may cause permanent damage to
the device. These are stress ratings only, and functional operation of the device at these or any other conditions
beyond those indicated under "Recommended Operating Conditions" is not implied. Exposure to "Absolute Maximum Ratings" for extended periods may affect device reliability.
AP3039 is a boost DC-DC controller with adjustable
operation frequency. Current mode control scheme
provides excellent line and load regulation. Operation
can be best understood by referring to Figure 3.
At the start of each oscillator cycle, the SR latch is set
and external power switch Q1 (see Figure 20) turns on
and the switch current will increase linearly. The
voltage on external sense resistor R
connected from CS pin to GND, is proportional to the
switch current. This voltage is added to a stabilizing
ramp and the result is fed into the non-inversion input
of the PWM comparator. When this non-inversion
input voltage exceeds inversion input voltage of PWM
comparator which is the output voltage of the error
amplifier EA, the SR latch is reset and the external
power switch turns off. The voltage level at inversion
input of PWM comparator sets the peak current level to
keep the output voltage in regulation. This voltage
level is the amplified signal of the voltage difference
between feedback voltage and reference voltage of
0.5V. So, a constant output current can be provided by
this operation mode.
(see Figure 20),
CS
Input Under-Voltage Detector
AP3039 contains an Under Voltage Lock Out (UVLO)
circuit. Two resistors R1 and R2 are connected from
UVLO pin to ground and VIN pin respectively (see
Figure 20). The resistor divider must be designed such
that the voltage on the UVLO pin is higher than 1.25V
when VIN is in the desired operating range. If the
voltage on the pin is below under voltage threshold, all
functions of AP3039 are disabled, but the system will
remain in a low power standby state. UVLO hysteresis
is accomplished through an internal 22µA current
source which switched on or off 22µA current into the
impedance of the set-point divider. When the UVLO
threshold is exceeded, the current source is activated to
instantly raise the voltage on the UVLO pin. When the
UVLO pin voltage falls below the threshold the current
source is turned off, causing the voltage on the UVLO
pin to fall. The formula for UVLO can be expresses as
blow:
For Input Threshold Voltage
V
IN_THRESHOLD
=1.25V*(R1+R2)/R2
For Input Hysteresis Voltage
V
IN-HYSTERESIS
=22µA*R1
Over Voltage Protection
AP3039 has an over voltage protection (OVP) circuit.
The OV Pin is connected to the center tap of R3 and R4
resistor voltage-divider from the high voltage output to
GND (see Figure 20). When the loop is open or the
output voltage becomes excessive in any case, result
the voltage on OV pin exceeds 1.25V, all functions of
AP3039 will be disabled, and the output voltage will
fall. OVP hysteresis is accomplished with an internal
22µA current source and the operation mode is the
same as UVLO. The formula for OVP can be expresses
as blow:
For OVP Voltage
V
=1.25V*(R3+R4)/R4
OVP
For OVP Hysteresis Voltage
V
OVP-HYSTERESIS
=22µA*R3
Frequency Selection
An external resistor R
, connected from RT pin to
T
GND, is used to set the operating frequency (see Figure
20). Operation frequency range is from 150kHz to
1MHz (see Table 1). High frequency operation
optimizes the regulator for the smallest component
size, while low frequency operation can reduce the
switch losses.
AP3039 has a soft start circuit to limit the inrush
current during startup. The time of soft start is
controlled by an internal 12µA current source and an
external soft start capacitor C
to GND (see Figure 20). The effective C
connected from SS pin
SS
voltage for
SS
Soft Start is from 0 to 2.3V, the time of Soft Start is:
t
= CSS*2.3V/12µA
SS
Typical Application
V
: 6V to 27V
IN
C
R1
R2
OFF ON
IN
VIN
UVLO
VCC
C
V
EN
VCC Pin Application Description
The AP3039 includes an internal low dropout linear
regulator with the output pin VCC. This pin is used to
power internal PWM controller, control logic and
MOSFET driver. On the condition that V
regulator generates a 6V supply. If 6V≤V
is equal to VIN minus drop voltage across bypass
V
CC
switch. When V
is less than 6V, connect VCC to
IN
≥8.5V, the
IN
≤8.5V, the
IN
VIN.
V
OUT
C
OUT
OUT
CS
L
Q1
R
D1
R3
R5
CS
R4
GND
OV
FB
SHDN
OFF ON
R6
RT
R
T
C
SS
R
C
C
C
SS
COMP
U1 AP3039
Figure 20. Application Circuit 1 of AP3039 (Note 2)
Note 2: The output voltage is decided by R5, R6 andthe internal 0.5V reference. The output voltage accuracy is
determined by the accuracy of R5 and R6, for which the precise resistors are preferred.
OUT
0.5V
=
()
R6R5*
R6
+
V
Note 3: In this application, the LED current is controlled by the feedback resistor R5. LEDs current accuracy is
determined by regulator
‘s feedback threshold accuracy and is independent of the LEDs‘ forward voltage variation.
So the precise resistors are the better choices. The resistance of R5 is in inverse proportion to the LED current
since the feedback reference is fixed at 0.5V. The relation of R5 and the LED current can be expressed as below:
0.5V
R5=
I
LED
Note 4: The summation of LED current is determined by R5 and internal 0.5V reference same as the illustration in
Figure 22.
More detailed application information please refer to application note.