AGAMEM AA18375AP

Agamem Microelectronics Inc.
PRELIMINARY
AA18375AP
Switching Regulator Controller
■OVERVIEW
The AA18375AP is a two-channel PWM DC-DC converter control IC that features low-voltage operation.
This IC can obtain the step-up, step-down and inverting voltages with a small number of external
components. Because the IC is compactly packaged, it is best suited for use as a power supply in
portable equipment.
■FEATURES
• Wide supply voltage range: 3.6 V to 15 V
• Low current consumption: 1.3 mA typical
• Control in a wide output frequency range is possible (1 kHz to 500 kHz).
• Timer latch, short-circuit protection circuit is built in.
• Circuit to prevent malfunction during low input voltage is built in.
• Built-in reference voltage (1.28V) output pin.
• Dead time period is adjustable over the whole range of duty ratio.
• Synchronization operation is possible.
■PIN Configuration
(TOP VIEW)
CT 1
16 VREF
RT 2
15 SCP
+IN1 3
14 +IN2
-IN1 4
13 -IN2
FB1 5
12 FB2
D.T.C.1 6
11 D.T.C.2
OUT1 7
10 OUT2
GND 8
9 VCC
■APPLICATIONS
• LCD Displays
• PDAs
• Digital Still Cameras
• Hand-held and portable instruments
©Copyright Agamem Microelectronics Inc.
1
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2006/6/27
AA18375AP
Agamem Microelectronics Inc.
PRELIMINARY
Switching Regulator Controller
■PIN DESCRIPTIONS
Pin No. Symbol I/O
1
CT
2
RT
3
+IN1
4
-IN1
5
FB1
6
D.T.C.1
7
OUT1
8
GND
Description
Pin No. Symbol
Pin for oscillation capacitor
connection
Pin for oscillation timing resistor
—
connection
Error amplifier 1 block
I
non-inverting input pin
Error amplifier 1 block inverting
I
input pin
Output pin of error amplifier 1
O
block
PWM1 block dead-time setting
I
pin
Output1 block push-pull type
O
output pin
—
— Ground pin
I/O
Description
9
VCC
I
IC power supply pin
10
OUT2
O
Output2 block push-pull type output pin
11
D.T.C.2
I
PWM2 block dead-time setting pin
12
FB2
O
Output pin of error amplifier 2 block
13
-IN2
I
Error amplifier 2 block inverting input pin
14
+IN2
I
15
SCP
—
16
VREF
O
Error amplifier 2 block non-inverting
input pin
Soft start and short circuit protection
setting capacitor connection pin
Reference voltage output pin
■ BLOCK DIAGRAM
Vcc
9
VREF 16
1.28V
CT
1
Reference
Voltage Supply
2.5V
1.9V
Triangular wave
Oscillator
1.3V
PWM Comp 1
+
_
_
Error Amp 1
+IN1 3
+
-IN1 4
-
+
+
_
OUTPUT 1
7
S.C.P.Comp
PWM Comp 2
FB1 5
FB2 12
RT
2
+
_
_
1.1V
OUTPUT 2
10
Error Amp 2
+IN2 14
+
-IN2 13
1.28V
2.5V
0.9V
SCP 15
0.9V
R
R
S
SET
CLR
Latch
U.V.L.O
Q
Q
+
+
_
D.T.C. Comp
1.8V
8
GND
©Copyright Agamem Microelectronics Inc.
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11
D.T.C. 1 D.T.C. 2
2
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Agamem Microelectronics Inc.
PRELIMINARY
AA18375AP
Switching Regulator Controller
■ ABSOLUTE MAXIMUM RATING
(Ta = +25 ° C)
Parameter
Symbol
Power Supply Voltage
Rating
Condition
Unit
Min
Max
VCC
-
-
18
V
Error Amp. Input Voltage
VI
-
-0.3
+10
V
Collector Output Voltage
VO
-
-
18
V
Collector Output Current
IO
-
-
75
mA
Power Dissipation
PD
Ta ≤ +25°C
-
*430
mW
Operating Temperature
TOP
-
-30
+85
°C
Storage temperature
Tstg
-
-55
+125
°C
*: The packages are mounted on the epoxy board (4 cm x 4 cm x 1.5 mm).
■ RECOMMENDED OPERATING CONDITIONS
Parameter
Value
Symbol
Unit
Min
Typ
Max
VCC
3.6
6.0
15
V
Error Amp. Input Voltage
VI
-0.2
–
1.45
V
Collector Output Voltage
VO
–
–
15
V
Collector Output Current
IO
0.3
–
50
mA
Phase Compensation Capacitor
CP
–
0.1
–
µ F
Timing Capacitor
CT
150
–
15000
pF
Timing Resistor
RT
5.1
–
100
kΩ
Oscillator Frequency
fOSC
1
–
500
kHz
Reference Voltage Output Current
IREF
–3
–1
–
mA
Operating Temperature
TOP
–30
25
85
°C
Power Supply Voltage
WARNING: The recommended operating conditions are required in order to ensure the normal operation of the
semiconductor device. All of the device’s electrical characteristics are warranted when the device is
operated within these ranges.
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Agamem Microelectronics Inc.
PRELIMINARY
AA18375AP
Switching Regulator Controller
■ ELECTRICAL CHARACTERISTICS
Parameter
Reference
Section
Under
Voltage
Lockout
Protection
Section
Protection
Circuit
Section
Triangular
Waveform
Oscillator
Section
condition
(Ta = +25 °C, VCC = 6 V)
Value
Symbol
Min
Typ
Max
Unit
Output Voltage
IOR = − 1 mA
VREF
1.26
1.28
1.30
V
Output Temp. Stability
Ta = − 30 ° C to +85 ° C
VRTC
–2
±0.2
2
%
Input Stability
VCC = 3.6 V to 15 V
Line
–
2
10
mV
Load Stability
IOR = − 0.1 mA to − 1 mA
Load
–
1
7.5
mV
Short Circuit Output
Current
VREF = 0 V
IOS
–
–30
–10
mA
IOR = − 0.1 mA
VtH
–
2.72
–
V
IOR = − 0.1 mA
VtL
–
2.60
–
V
IOR = − 0.1 mA
VHYS
80
120
–
mV
Threshold Voltage
Hysteresis Width
Reset Voltage (VCC)
–
VR
1.5
1.9
–
V
Input Threshold Voltage
–
VtPC
0.60
0.65
0.7
V
Input Stand by Voltage
No pull up
VSTB
–
50
100
mV
Input Latch Voltage
No pull up
VI
–
50
100
mV
Ibpc
–1.4
–1.0
–0.6
µ A
Input Source Current
–
Comparator Threshold
Voltage
Pin 5, Pin 12
VtC
–
1.1
–
V
Oscillator Frequency
CT = 330 pF, RT = 15 kΩ
fOSC
–
200
–
kHz
Frequency Deviation
CT = 330 pF, RT = 15 kΩ
fdev
–
10
–
%
Frequency Stability (VCC) VCC = 3.6 V to 15 V
fdV
–
1
–
%
Frequency Stability (Ta)
Ta = − 30 ° C to +85 ° C
fdT
–4
–
4
%
Input Threshold Voltage
Duty Cycle = 0 %
Vt0
–
1.0
VREF
−0.15
V
Vt100
0.2
0.4
–
V
Ibdt
–
–0.2
–1
µ A
–
–150
–80
µ A
–
–
V
Dead-Time (fOSC = 10 kHz)
Control
Input Bias Current
Section
Duty Cycle = 100 %
–
Latch Mode Source
Current
Vdt = 0.7 V
Idt
Latch Input Voltage
Idt = − 40 µ A
Vdt
VO = 1.6 V
VIO
–10
–
+10
mV
VO = 1.6 V
IIO
–100
–
+100
nA
Input Bias Current
VO = 1.6 V
IB
–500
–100
–
nA
Common Mode Input
Voltage Range
VCC = 3.6 V to 15 V
VICR
–0.2
–
+1.45
V
AV
84
120
–
V/V
BW
–
3
–
MHz
Error Amp. Input Offset Voltage
Section
Input Offset Current
Voltage Gain
Frequency Band Width
©Copyright Agamem Microelectronics Inc.
AV = − 3 dB
4
VREF−0.1
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Agamem Microelectronics Inc.
PRELIMINARY
Switching Regulator Controller
Common Mode Rejection
Ratio
Max Output Voltage
Width
CMRR
60
80
–
dB
VOM+
2.2
2.4
–
V
VOM
–
0.7
0.9
V
Output Sink Current
VO = 1.6 V
IOM+
24
50
–
µ A
Output Source Current
VO = 1.6 V
IOM
–
–1.2
–0.7
mA
Input Threshold Voltage
(fOSC=10 kHz)
Duty Cycle = 0 %
Vt0
–
1.9
2.1
V
Vt100
1.05
1.3
–
V
Pin 5, Pin 12 = 1.6 V
IIN+
24
50
–
µ A
Input Source Current
Pin 5, Pin 12 = 1.6 V
IIN
–
–1.2
–0.7
mA
Output Leak Current
VO = 15 V
Leak
–
–
10
µA
VSAT
–
1.1
1.4
V
PWM
Comparator
Input Sink Current
Section
Output
Section
AA18375AP
Duty Cycle = 100 %
Output Saturation Voltage IO = 50 mA
Stand by Current
Output “OFF”
ICCS
–
1.3
1.8
mA
Average Supply Current
RT = 15 kΩ
ICCa
–
1.7
2.4
mA
■ TIMING DIAGRAM
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Agamem Microelectronics Inc.
PRELIMINARY
AA18375AP
Switching Regulator Controller
■ TYPICAL CHARACTERISTICS
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Agamem Microelectronics Inc.
PRELIMINARY
©Copyright Agamem Microelectronics Inc.
AA18375AP
Switching Regulator Controller
7
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Agamem Microelectronics Inc.
PRELIMINARY
AA18375AP
Switching Regulator Controller
■ OPERATION DESCRIPTION
1. Reference voltage
This block is composed of the band gap circuit, and outputs the temperature compensated 2.5 V reference from
Vcc (pin 9) for use by internal circuits. A reference voltage of temperature compensated 1/2 Vref can be
obtained to external circuit by Vref terminal (pin 16).
2. Oscillator
The sawtooth-waveform-like triangular wave having a peak of approximately 1.9 V and a trough of
approximately 1.3 V can be generated by connecting the timing capacitor CT (pin 1) and resistor RT (pin 2).
The usable oscillation frequency is from 1 kHz to the maximum 500 KHz. The triangular wave is
connected with the non-inverting input of PWM comparator for channel 1 side and channel 2 side within
the IC inside.
3. Error amplifiers
The output voltage of DC-DC converter is detected by the error-amplifier and the amplified signal is input
to the PWM comparator. Also, it is possible to perform the gain setting and the phase compensation
arbitrarily by connecting a resistor and a capacitor from the FB terminals (pins 5 and 12) to GND. The
error amplifier output is internally connected to the inverting inputs of the PWM comparators and also to
the short protection circuit.
4. Timer latch short protection circuit
This circuit protects the external main switching devices, flywheel diodes, and choke coils, etc. from
destruction or deterioration if overload or short-circuit condition of power supply output lasts for a certain
time. The timer latch short-circuit protection circuit detects the output level of the error amplifier. If one or
both error amplifier outputs are 1.1 V or lower, the low-level output is given and the timer circuit is
actuated to start the charge of the external protection-enable capacitor.
If the output level of the error amplifier does not drop below the normal voltage range before the capacitor
voltage reaches the 1.19 V, it sets the latch circuit, and cuts off the output drive transistor, and sets the
dead-time to 100%.
5. Under voltage lockout protection circuit
This circuit protects the system from destruction or deterioration due to control malfunction when the
supply voltage is low in the transient state of power on/off. The under voltage lockout protection circuit
compares the internal reference voltage level with the supply voltage level. If the supply voltage level falls
below the reference level it cuts off the output drive transistor, and sets the dead time to 100%. The
protection enable terminal (pin 15) is pulled “Low”.
6. PWM comparator
Each PWM comparator has two inverting inputs and one non-inverting input. This voltage-to-pulse-width
converter controls the output pulse width according to the input voltage. The PWM comparator turns the
output drive transistor on when the oscillator triangular waveform is higher than the error amplifier output
and the dead time control terminal voltage.
7. Output drive transistor
This output circuit is open-collector type. The available output current is up to 50 mA. The breakdown
voltage of output terminal is 15V.
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2006/6/27
AA18375AP
Agamem Microelectronics Inc.
PRELIMINARY
Switching Regulator Controller
■ TEST CIRCUIT
+IN2
15
16
4.7KΩ
OUT2
CPE
1.28V
VCC
SW
DTC2 INPUT
FB2 TEST
14
4.7KΩ
-IN2
13
12
11
10
9
6
7
8
OUT1
2
1
3
4
5
0.1uF
+IN1
15KΩ
330pF
-IN1
FB1 TEST
DTC1 INPUT
AA18375AP
GND
■ TYPICAL APPLICATION EXAMPLE
820pF
10KΩ
2.3KΩ
0.1uF
33KΩ
1uF
33KΩ
+ 33KΩ
1
16
2
15
3
14
Vin (10V)
Chopper Type Step Down/Inverting
0.1uF
4
AA18375AP
56uH
1.9KΩ
13
0.1uF
5
12
6
11
7
10
8
9
220uF
33KΩ
- +
1uF
5.6KΩ
+ 330Ω
330Ω
470Ω
470Ω
120uH
9.1KΩ
220uF
- +
- +
GND
9
120uH
Vout+(+5V)
Vout-(-5V)
©Copyright Agamem Microelectronics Inc.
220uF
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2006/6/27
AA18375AP
Agamem Microelectronics Inc.
PRELIMINARY
Switching Regulator Controller
Vin (5V)
Chopper Type Step Up/Inverting
820pF
2.3KΩ
16
2
15
3
14
4
0.1uF
33KΩ
1uF
1
0.1uF
10KΩ
33KΩ
+ 33KΩ
AA18375AP
56uH
1.9KΩ
13
0.1uF
5
12
6
11
7
10
8
9
220uF
33KΩ
- +
1uF
16KΩ
+ -
330Ω
330Ω
3.9KΩ
120uH
100Ω
120uH
9.1KΩ
220uF
- +
- +
GND
820pF
2.3KΩ
0.1uF
33KΩ
33KΩ
+ 33KΩ
1uF
+ -
16
2
15
3
14
4
13
0.1uF
10KΩ
1uF
1
Vin (5V)
Chopper Type Step Up/Inverting (For High Speed)
Vout+(+12V)
Vout-(-5V)
220uF
AA18375AP
56uH
1.9KΩ
0.1uF
5
12
6
11
7
10
8
9
220uF
33KΩ
- +
16KΩ
470Ω
470Ω
220Ω
470Ω
470Ω
33KΩ
330pF
220uF
220uF
- +
- +
GND
10
Vout+(+12V)
Vout-(-5V)
©Copyright Agamem Microelectronics Inc.
120uH
33KΩ
120uH
9.1KΩ
150Ω
- 1uF
+
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2006/6/27
Agamem Microelectronics Inc.
PRELIMINARY
AA18375AP
Switching Regulator Controller
■ HOW TO SET OUTPUT VOLTAGE
The output voltage is set using the connection shown below. The error amplifiers are supplied to the
internal reference voltage circuit as are the other internal circuits. The common-mode input voltage range
is from − 0.2 V to +1.45 V. When the amplifiers are operated non-inverting, tie the inverting terminal to
VREF≒1.28 V). When the amplifiers are operated inverting, tie the non-inverting terminal to ground.
R2
Vo+ [=Vref X (1+R2/R1)]
+
-
R1
PIN5 or PIN12
Vref
R2
Vo- [= -Vref X (R2/R1)]
-
R1
+
PIN5 or PIN12
Vref
■ HOW TO SET TIME CONSTANT FOR TIMER LATCH SHORT PROTECTION CIRCUIT
If the load condition drastically changes due to a load short-circuit and if low-level signals (1.1 V or lower)
are input to the non-inverting inputs of the short-circuit protection comparator from the error amplifiers, the
short circuit protection comparator outputs a “Low” level. The protection enable terminal voltage is
discharged, and then the short-circuit protection comparator charges the externally connected protection
enable capacitor CPE according to the following formula:
-6
VPE = 50 mV + tPE x 10 /CPE
-6
0.65 = 50 mV + tPE x 10 /CPE
CPE = tPE/0.6 (µ F)
When the power supply is turned on, the output is considered to be short-circuited state so that the S.C.P.
terminal voltage starts charging. It is necessary to set the external capacitor so as to start up the DC-DC
converter output voltage before setting the latch circuit in the later stage. Especially, pay attention to the
delay of the start-up time when applying the soft-start function.
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Agamem Microelectronics Inc.
PRELIMINARY
AA18375AP
Switching Regulator Controller
■ SYNCHRONIZATION OF ICs
Multiple instances of this IC can be operated in parallel. If the CT and RT terminals are connected to each
other as shown below, the ICs will operate at the same frequency. Instead of applying VRT to the RT
terminals, these terminals can be pulled up by a resistor (see resistance indicated by the dashed line in).
Select the pull-up resistance Rpull from the formula given below.
Vcc
0.5 x N
≤ Rpull
16
15
Rpull: Pull up Resistor (kΩ)
VCC: Power Supply Voltage (V)
N: Number of Slave ICs
14
13
12
11
10
9
AA18375AP
(MASTER)
1
2
3
Vcc
4
5
6
7
8
13
12
11
10
9
RT
CT
Rpull
16
15
14
AA18375AP
(SLAVE)
VRT
2V
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
7
8
AA18375AP
(SLAVE)
1
©Copyright Agamem Microelectronics Inc.
2
3
5
4
12
6
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AA18375AP
Agamem Microelectronics Inc.
PRELIMINARY
Switching Regulator Controller
■PACKAGE
AA18375AP - 16-pin Plastic TSSOP
E1
E
L
C
AA18375AP
12º(4X)
A1
A
A2
theta
D
SYMBOLS
A
A1
A2
b
C
D
E
E1
e
L
y
theta
DIMENSIONS IN MILLIMETERS
MIN
NOM
MAX
--0.05
0.80
0.19
0.09
4.90
6.20
4.30
--0.45
--0°
----1.00
----5.00
6.40
4.40
0.65
0.60
-----
e
DIMENSIONS IN INCHES
MIN
NOM
MAX
--0.002
0.031
0.007
0.004
0.193
0.244
0.169
--0.018
--0°
1.20
0.15
1.05
0.30
0.20
5.10
6.60
4.50
--0.75
0.10
8°
b
----0.039
----0.197
0.252
0.173
0.026
0.024
-----
0.048
0.006
0.041
0.012
0.008
0.201
0.260
0.177
--0.030
0.004
8°
NOTE
1. PACKAGE BODY SIZES EXCLUDE MOLD FLASH PROTRUSIONS OR GATE BURRS
2. TOLERANCE ±0.1 mm UNLESS OTHERWISE SPECIFIED
3. COPLANARITY : 0.1 mm
4. CONTROLLING DIMENSION IS MILLIMETER. CONVERTED INCH DIMENSIONS ARE
NOT NECESSARILY EXACT.
5. FOLLOWED FROM JEDEC MO-153
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Agamem Microelectronics Inc.
PRELIMINARY
AA18375AP
Switching Regulator Controller
■NOTES ON USE
• The information described herein is subject to change without notice.
• The specifications for the product described in this document are for reference only. Upon actual
use, therefore, please request that specifications to be separately delivered.
• The application circuit examples explain typical applications of the products, and do not
guarantee the success of any specific mass-production design.
• Application circuit diagrams and circuit constants contained herein are shown as examples of
standard use and operation. Please pay careful attention to the peripheral conditions when
designing circuits and deciding upon circuit constants in the set.
• Take account of common impedance when designing the earth line on a printed wiring board.
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