Page 1
ICs for CD/CD-ROM Player
■ Overview
The AN8083S is an IC for controlling a DC-DC converter suitable for the switching power supply of various
portable equipments. It can operate with input voltage
1.1V or more.
■ Features
•
Operatable with low voltage input (PV
CC
>1.1V)
•
Decreased voltage detection circuit built-in
•
Short-circuit protection feature built-in
•
Provided with reset output
•
Synchronizable with outside clock
•
Low consumption current in stand-by mode
•
Output voltage in secondary side; 4.8V+0.3V (Variable
by using external resistance)
AN8083S
Low Voltage Operation IC for DC-DC Converter
0.1±0.1
1.5±0.2
0.3
0.65
0.15
0.4
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
0.4±0.25
1.27
Unit : mm
6.5
±0.3
4.2±0.3
10.1±0.3
16-lead SOP package (SOP016-P-0225A)
15 1316 14 7
1 2 3 4 5
6
V
SEN
PV
CC
IN
10 12
9
8
11
Power
OFF
63kΩ
–+
GND
0.9V
1.25V
0.7V
4.2V
0.725V
30kΩ
2.0V
4.8V
1.25V 3.0 → 2.5V
2.15V
0.25V
0.85V
V
REF
–25µA
–+
–
+
+
–
+
–
+
–
+
RESET
EMP START
V
REF
CT
CLK
POWER
FB SPRO DED OUT
Starter SW
Early Value Set.
Starter
Switching
Circuit
Triangular
Wave
V
CC
■ Block Diagram
Page 2
ICs for CD/CD-ROM Player
AN8083S
V
CC
PV
CC
P
D
T
opr
T
stg
Supply Voltage
Power Dissipation
Operating Ambient Temperature
Storage Temperature
V
mW
˚C
˚C
Parameter Symbol Rating Unit
■ Absolute Maximum Ratings (Ta=25˚C)
14.4
14.4
380
–20 ~ +75
–55 ~ +125
Paramenter Symbol Range
■ Recommended Operating Range (Ta=25˚C)
Operating Supply Voltage Range
V
CC
PV
CC
1.8V ~ 12V
1.1V ~ 12V
Parameter Symbol Condition min. typ. max. Unit
■ Electrical Characteristics (Ta=25˚C)
Power VCC Stand-by Mode Supply Current
I
PVCC
2 µA
V
CC
=0V, PVCC=3V
Power VCC Operating Mode Supply Current
I
PVCC
3 mA1.2
V
CC
=3.1V, PVCC=3V
Output Voltage
V
O
V4.8
Reset Output Threshold Voltage
4V
TH (RESET)
4.4 V
PV
CC
=3V
Decreased Voltage Detection Threshold Voltage
2.05V
TH (VSEN)
2.25 V2.15
PV
CC
=3V
Short-Circuit Protection Operating Voltage
1.35V
O (SPRO)
2.1 V
V
IN
=0V, V
POWER
=2V
Short-Circuit Protection Operating Voltage
1.7V
O (SPRO)
3.2 V
V
IN
=1V, V
POWER
=0V
Oscillation Frequency in Normal Operation
60f
OSC1
80 kHz70
R
REF
=33kΩ, CT=330pF
f
OSC2
80
100 120
kHzOscillation Frequency at Start
R
REF
=33kΩ, CT=330pF
V
CC
=1.9V, PVCC=3V
Output Voltage (Normal)
1.2V
OH (OUT)
1.6 V
I
O
= –20mA, VCT=0V
Output Voltage (Normal)
V
OL (OUT)
0.4 V
I
O
=20mA, VCT=1V
Note) Unless otherwise specified, V
CC
=4.8V, PVCC=3V
4.2
15 16 13 14 10 7 12
9
8
11
6
54321
+
2.15V
V
REF
4.8V
4.2V
0.7V
1.25V
2.0V
0.9V
30kΩ
–25µA
63kΩ
+
–
+
–
+
–
+
–
+
+ –
3.0V→ 2.5V
33kΩ
0.01µF
IN FB
SPRO
47µF
DED
0.01µF
OUT
GND
0.01µF
100Ω
POWER
CLK
PV
CC
4.8V±0.3V
33kΩ330pF
V
REF
CT
START
V
SENSE
EMP
V
CC
+ –
Power
OFF
0.25V
0.85V
1.25V
Connect Pin11 to the secondary side and Pin10 to GND at oscillation start. (Pin10 is always open.)
RESET
0.725V
Starter SW
Initial set
Starter
SW
circuit
+
Triangular
Wave
■ Application Circuit
Page 3
ICs for CD/CD-ROM Player
AN8083S
■ Pin Description
Pin No.
Symbol
1 IN
•
Input pin for error amplifier
•
Threshold voltage ; 0.7V
2 FB • Output pin for error amplifier
•
Short-circuit protection input pin.
If output of error amplifier does not become “L” when t=CVth/I
SPRO
output of IC is not
switched. I
SPRO
=25µA
Vth=0.9V
3 SPRO
4 DED
• Dead time control input.
Maximum duty ratio set to 85%.
5 OUT
•
Switching output pin
Output current ; IO=20mA (max.)
6 GND • GND pin
• Triangular oscillating capacitor pin
7 CT
8 PV
CC
• DC voltage input pin
Operates with 1.2V or more.
•
Clock input
· It is used to synchronize triangular oscillation with clock input and operates at rise edge of
clock.
· The threshold level is TTL level.
· It is open when not used.
9 CLK
•
Start pin
· Starts switching of starter
· Threshold voltage, PV
CC
– 0.9V
10 START
11 POWER
•
Power ON/OFF pin
Output ON/OFF switching pin (Output is off at “L.”)
Maximum duty ratio can be changed by installing
external resistance between Pins 12 and 4.
T
1
T
2
V
T1 =
CV
I (Discharged)
f =
1
T
1+T2
T2 =
CV
I (Charged)
I Discharged=52µA
I Charged=30µA
V=0.58V
• Reference voltage pin
· 1.25V output
· Charged and discharged current of triangular oscillation is determined by external R.
I (Charged) =
V
REF
– 0.7
R
REF
+1kΩ
I (Discharged) =1.40 × I (Charged)
12 V
REF
13 EMP
•
Decreased voltage detection output pin
“H” when detected by open collector output form
14 V
SEN
• Decreased voltage detection input pin
· Threshold voltage ; 2.15V
•
Reset output pin
· “H” when VCC becomes 4.2V or more
· Open collector output form
15 Reset
16 V
CC
• DC voltage input pin
Operates with 1.8V or more.
In normal mode
Pin Description
Page 4
ICs for CD/CD-ROM Player
AN8083S
8
9
10
11
5
16
1315
+
1.5V
1.5V
SW
Oscillation starts at “L.”
“L” when the battery voltage is 2.15V or less.
“H” when the secondary voltage is 4.2V or more.
Oscillation synchronization signal
Power OFF at “L”
P–V
CC
V
CC
OUT
AN8083S
Power SW
Start
CPU
1) When Pin10 becomes “L” by operation of CPU or
push switch, oscillation starts and boosted voltage is
outputted to the secondary side.
2) When the secondary side voltage exceeds 3.6V, starter
circuit is stopped and PWM operation is started by using
the voltage in the secondary side as power supply.
3) When the secondary side voltage becomes 4.2V,
Pin15 becomes “H” and CPU operation is started.
4) When “L” pulse is sent from CPU to Pin11, oscillation
is stopped and it enters the stand-by mode. In this
status consumption current is 2µA max.
5) For re-start, when Pin10 becomes “L” by operation of
CPU or push switch, oscillation starts.
CLK
RESET
EMP
■ System Block Diagram
■ Supplementary Explanation
• Operational Description
When power VCC pin (Pin8) is connected to the supply output and start pin (Pin10) is set to “Low,” the triangular oscillation is
outputted to CT pin (Pin7) and the rectangular wave to OUT pin (Pin5). In this condition, called start condition, PWM control is not
obtained and only oscillation is repeated. By this oscillation at start, supply output is increased. This supply output voltage is
inputted to VCC pin (Pin16) of the AN8083S. When the voltage of VCC pin becomes 3V or more, start oscillation is stopped and
oscillation in normal operation is outputted. PWM control is started only after entering normal mode. The voltage switching
between start and normal operation has 0.5V hysteresis. When power pin (Pin11) is set to “High” in normal operation, normal mode
oscillation is started. In this status, output of the supply is 4.8V fixed.
• Other features
1. Short-circuit protection feature
For normal mode oscillation, when output/FB pin (Pin2) of error amplifier is in “High” condition, oscillation is stopped, since the
power supply system is judged to be in an abnormal condition. With the time constant of discharged current I
(Pin3) and capacitor C
when the error amplifier becomes “Low,” charged current no longer exits and SPRO is maintained to 0.9V.
2. Decreased voltage detection circuit
When V
3. Reset output
When VCC pin voltage is 4.2V or more, RST pin (Pin15) gets “High.”
, pin voltage is increased, and oscillation is stopped when it becomes 1.25V or more. During this time,
SPRO
pin (Pin14) gets 2.15V or less, EMS pin (Pin13) gets “High.”
SEN
of SPRO pin
SPRO
Page 5
ICs for CD/CD-ROM Player
AN8083S
• Miscellaneous
1. Method for making output voltage variable
V
CC
= 0.7V × (R1 + R2)/R
2
R1 = RX // R
3
R2 = RY // R
4
ex) Where V
CC
= 5V,
RX = 51kΩ
RY = 7.5kΩ
2. Method for making decreased voltage detection variable
V
SEN
=
R1 + R
2
× 1.25
R
2
ex) V
SEN
= 3V
V
SEN
=
R1 + R2 + R
3
× 1.25
R
2
R3 = 7kΩ
However, take care that an external resistance causes different temperature characteristics.
3. Reset output
When the output voltage is made variable, detection voltage changes.
V
CC
= 4.8V→ 4.2V (No changes)
V
CC
= 5V→ 4.27V
• Chopper type application
51kΩ
7.5kΩ
3.64kΩ
3.5kΩ
15
1.25V
16.86kΩ
16
1
51kΩ
16
1 2
8
5
AN8083S
33kΩ
0.01µF
100Ω
0.01µF
100Ω
0.01µF
2SD1328
2SD1328
4.8V±0.3V
R
X
R
Y
R3 =20.5kΩ
R
4
=3.5kΩ
V
CC
(16)
IN (1)
R1 =7kΩ
R
2
=10kΩ
V
SEN
(14)R
3
7.5kΩ
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