AKM AP2200

[ AP2200]
AP2200
Step-up DC/DC converter IC supporting 1 or 2 solar cells
OVERVIEW
The AP2200 is a voltage step-up DC/DC converter using the synchronous rectification method to
be activated with 1 or 2 solar cells and is ideal for charging lithium-ion batteries or outputting USB
VBUS voltage. Also, the MPPT (Max Power Point Tracking) function is embedded in order to
maximize the output power from the solar cells.
FEATURES
 Input voltage range
0.4 V to 1.6 V
 Operating temperature range
-30 to 85°C
 Input power
Up to 400 mW per 1 cell
Up to 800 mW per 2 cells
 Output voltage
4.0 V (±2%) per 1 cell
5.0 V (±5.0%) per 2 cells
 Control method
Comparator control method
 Rectification method
Synchronous rectification method
 Standby function
When the STBY pin is H, the LC pin is fixed to H
 No battery detect function
When the VB pin voltage decreases, the LC pin is fixed to H
 Efficiency
70% (1 cell input, 4.0 V, 50 mA output),
80% (2 cells input, 5.0 V, 80 mA output)
 Package
QFN 16 pin
 Application
For charging a lithium-ion battery and
USB VBUS source with 1 or 2 solar cells
MS1462-E-00
1
[ AP2200]
BLOCK DIAGRAM
Set output voltage to 4 V
1uF
VREG
LDO
When connected to battery
REF
To other equipment
Logic
BAT
VB
OSC
MCU
STBY
LC
Load
Control
4V±1.5%
C1
VOUT 0.1uF
VOUT
Monitor
SEL
L
SW
PreDriver
VIN
Monitor
0.01uF
PG
TEST1
Start Up
TEST2
GND
1
PG
2
VCP
3
VIN
4
SW
VOUT
VOUT
15
14
13
16 PIN
3 x 3 mm QFN
5
6
7
8
GND
VREG
SEL
TEST1
MS1462-E-00
PG
SW
PIN LAYOUT
16
2
Solar cell
0.4V~0.8V
(1 cell
400mW)
10uF
VIN
VCP
10uF
12
LC
11
VB
10
STBY
9
TEST2
(Top View)
[ AP2200]
I/O PINS & FUNCTIONS
Table 1 Pin functions
Pin No
Pin name
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
EP
PG
PG
VCP
VIN
GND
VREG
SEL
TEST1
TEST2
STBY
VB
LC
VOUT
VOUT
SW
SW
GND
Type
(Note1)
GND
GND
A
PWR
GND
A
D
D
A
D
A
A
A
A
GND
I/O
(Note2)
IO
IO
I
I
I
O
IO
IO
IO
IO
-
Description
DC/DC ground pin
DC/DC ground pin
Charge pump pin
Power input pin
Ground pin
Internal regulator output pin
Output voltage switch input pin
Test pin
Test pin
Standby input pin
Battery monitoring input pin
External switch control pin
DC/DC output pin
DC/DC output pin
Inductor connect pin
Inductor connect pin
Tab pin
Note 1:
A: analog pin, D: digital pin, GND: ground pin, PWR: power pin
Note 2:
I: input pin, O: output pin, IO: input and output pin
Note 3:
The test pin should be connected to GND.
Note 4:
The tab pin may be connected to GND or left open.
MS1462-E-00
3
Remarks
L: 4 V / H: 5 V
(Note3)
(Note3)
H: standby
(Note4)
[ AP2200]
ABSOLUTE MAXIMUM RATINGS
Table 2 Absolute maximum ratings
TA = 25ºC except as otherwise noted
Item
Symbol
VIN1
Pin voltage Range
(Note1)
VIN2
Input power
PIN
Operational temperature
TA
Range
Storage temperature Range
TSTG
Junction temperature
TJ
Power dissipation
PD
Min
-0.3
-0.3
Max
1.98
5.5
0.8
Unit
V
V
W
-30
85
°C
-40
150
150
0.8
°C
°C
W
Note 1:
The voltage is based on ground pin voltage.
Note 2:
If the absolute maximum rating is exceeded, the device may be damaged.
Remarks
Note3
Note4
Also, normal behavior cannot be guaranteed.
Note 3:
VIN pin and VREG pin
Note 4:
VCP pin, SEL pin, STBY pin, VB pin, LC pin, VOUT pin and SW pin
OPERATING CONDITIONS
Table 3 Operating conditions
Item
Supply voltage range
Symbol
VIN
Supply voltage on startup
VINSTUP
Operational temperature
TA
Note 1:
Condition
-30°C < TA <-10°C
-10°C < TA <85°C
The voltage is based on the ground pin.
MS1462-E-00
4
Min
0.4
0.5
0.4
-30
Typ
Max
1.6
Unit
V
-
1.6
V
-
85
°C
[ AP2200]
ELECTRIC CHARACTERISTICS
Table 4 Electric characteristics
TA = 25ºC except as otherwise noted
Item
Symbol
DC/DC converter
VOUT voltage
(Note3)
VOUT hysteresis
High-side on resistance
Low-side on resistance
Switching frequency
Low-side current limit
(Note 2)
MPPT circuit
VPM open circuit voltage
ratio
Open circuit voltage
sampling period
Monitoring circuit
No battery detect voltage
Low VOUT detect voltage
Logic I/O
Min
Typ
Max
3.96
4.0
4.04
3.92
4.0
4.08
4.75
5.0
5.25
VTGTHYS
RONTOP
RONBOT
fOSC
0.16
0.60
450
0.38
0.2
0.1
500
550
kHz
ILIM
0.9
1.2
1.5
A
78
80
82
%
tSH
90
100
110
ms
VBLOW
VOL
1.0
2.35
2.65
2.5
2.90
V
V
-
-
GND+0.1
VOUT-0.45
VB-0.45
-
-
VILSTB
VIHSTB
VILSEL
1.0
-
-
0.3
VOUT*0.3
VIHSEL
VOUT*0.7
-
-
VREG
fCK
1.62
0.9
1.8
1.0
1.98
1.1
V
MHz
-
-
50
A
-
10
20
A
0.5
0.5
-
1.5
1.5
MΩ
MΩ
VTGT
MPP
VOLLC
External switch driving
voltage
Standby input voltage
Output voltage switching
input voltage
(Note 4)
Control part
Internal regulator voltage
Operating frequency
Pin current
VIN pin current
VOHLC
IVIN
VB pin current
IVB
Internal pull-down resistance
STBY pin
RPDSTBY
SEL pin
RPDSEL
Condition
TA = 25 ºC, SEL=0
TA = -30 to 85ºC ,
SEL=0
TA = -30 to 85ºC ,
SEL=1
MPP=VPM/VOC
I=-1uA
I=1uA
VOUT>VB
VOUT<VB
During normal
operation:
VIN<1.2V@ TA >25°C
VIN<1.6V@ TA <25°C
LC=H/L
Note 1:
The voltage is based on the ground pin.
Note 2:
Not tested in mass production.
Note 3:
Only tested at TA = 25ºC in mass production.
Note 4:
Connect the SEL pin to the VOUT or the GND pin.
MS1462-E-00
5
Unit
V
%
Ω
V
V
V
[ AP2200]
OPERATION DETAILS
1. Operation overview
When the output voltage is entered into VIN from the solar cell(s), the low voltage startup circuit
starts to step up the output voltage (VOUT). When VOUT reaches the voltage required for operation of
the step-up converter, the low voltage startup circuit stops and the step-up converter starts. After that,
the step-up converter increases VOUT to the target voltage (VTGT) and controls VOUT so that it will be
stabilized at VTGT. Also, when VOUT reaches VTGT, the step-up converter decreases the LC pin to a low
level. For the application where an external PMOS load switch is connected to the LC pin, when the
LC pin becomes a low level, the external switch is turned ON to start the power supply to the
equipment. However, if one of the conditions below is met, the external load switch is turned OFF to
stop the power supply:
 The STBY pin is set to a high level:
The AP2200 has a standby function. When the STBY pin is set to a high level (VIHSTB) by
applying voltage, the external load switch is turned OFF to stop the power supply. The step-up
converter is still running even in a standby state. When the STBY pin is set to a low level
(VILSTB) by applying voltage, the standby mode is released to start the power supply.
 The VB pin voltage is less than or equal to VBLOW:
The AP2200 has a battery monitoring function. When the VB pin voltage deceases to VBLOW or
lower, a battery is assumed to be removed and the external load switch is turned OFF to stop
the power supply. When the VB pin voltage increases to VBLOW or higher, a battery is assumed
to be reinserted and the external load switch in turned ON to start the power supply.
To disable this function, connect the VB pin to the VOUT pin.
 The VOUT pin voltage is less than or equal to VOL:
When the VOUT pin voltage decreases to VOL and lower, the external load switch is turned OFF
to stop the power supply. The step-up converter is still running. When VOUT reaches VTGT again,
the power supply is restarted.
 When sampling the open circuit voltage (VOC) of the solar cell(s) per the cycle tSH,
The AP2200 turns OFF the external load switch as well as pausing the voltage step-up
operation. When the sampling of the open circuit voltage comes to an end, the voltage step-up
operation resumes. Unless VOUT reaches VTGT again, the external load switch is not turned ON.
This prevents back flow from the battery to VOUT to minimize the battery consumption when the
power supply from the solar cell(s) decreases, and the step-up converter cannot increase the
voltage sufficiently.
MS1462-E-00
6
[ AP2200]
2. Output voltage setting
The output voltage (VTGT) is selectable based on the SEL pin. (Table 5)
Table 5 Output voltage setting
SEL pin level
0
1
Output voltage (VTGT)
setting
4V
5V
3. MPPT control
The voltage step-up operation is paused per the cycle tSH and the open circuit voltage (VOC) of the
solar cell(s) is sampled. This PWM function first calculates the voltage (VPM) from VOC where the
maximum output can be obtained based on the solar cell properties and then controls the step-up
converter to obtain the voltage.
4. Output voltage control
The step-up converter always monitors VOUT. As soon as VOUT reaches the setting voltage (VTGT),
the converter stops the voltage step-up. When the voltage step-up operation is stopped, VOUT
decreases due to load consumption. When VOUT drops by VTGTHYS or more form VTGT, the step-up
operation is restarted.
MS1462-E-00
7
[ AP2200]
5. Timing chart
Note:
A timing chart only shows an operation overview and the scale of time and voltage is not
accurate.
5.1. Normal operation (the voltage increases to VOUT after startup)
LC pin
H
L
STBY pin
H
L
Step-up
operation stop
Pin voltage
VTGT
VTGT-VTGTHYS
VOL
VBLOW
VOUT
VB
VOC
VPM
Internal initialization and
open circuit voltage
sampling
(voltage step-up stop)
MS1462-E-00
Open circuit voltage sampling
(step-up operation stop)
Open circuit voltage sampling
(step-up operation stop)
Open circuit voltage
sampling period tSH
8
[ AP2200]
5.2. Behavior when solar cell output decreases
LC pin
H
L
STBY pin
H
L
Solar cell output
decreases
Step-up
operation stop
Pin voltage
VTGT
VTGT-VTGTHYS
VOUT
VB
VOL
VBLOW
VOC
VPM
Open circuit voltage sampling
(step-up operation stop)
Open circuit voltage sampling
(step-up operation stop)
Open circuit voltage
sampling period tSH
MS1462-E-00
9
Open circuit voltage sampling
(step-up operation stop)
[ AP2200]
5.3. Behavior when the STBY pin is asserted
LC pin
H
L
STBY pin
Set STBY to H
Set STBY to L
H
L
Step-up
operation stop
Pin voltage
VTGT
VTGT-VTGTHYS
VOUT
VB
VOL
VBLOW
VOC
VPM
Open circuit voltage sampling
(step-up operation stop)
Open circuit voltage sampling
(step-up operation stop)
Open voltage sampling
period tSH
MS1462-E-00
10
Open circuit voltage sampling
(step-up operation stop)
[ AP2200]
5.4. Behavior when no battery is connected.
MS1462-E-00
11
[ AP2200]
REFERENCE DESIGN

Application schematics
Set output voltage to 4V
When connected to battery
To other equipment
Solar cell
0.4 to 0.8V
(1 cell 400mW)
Set output voltage to 5V
When connected to USB
Solar cell
0.8 to 1.6V
(2 cell 800mW)
Note1:
Select the C1 value to prevent the LC pin voltage from exceeding the absolute maximum
rating due to the current through parasitic capacitance of the external load switch.
MS1462-E-00
12
[ AP2200]
Note2:
Please refer to table 6 for external components.
Item
Ceramic
Capacitors
Inductors
Load
switches
MS1462-E-00
Table 6．Reference design list of materials
Symbol
Part number
Manufacturer
CIN
COUT
CREG
CCP
CLC
L1
SLF6045T-4R7N2R4-3PF TDK
L2
SLF6045T-6R8N2R0-3PF TDK
M1,
NTS2101P
On
M2
Semiconductor
13
Value
10F
10F
1F
0.01F
0.1F
4.7H
6.8H
-
AsahiKASEI
AKM confidential
[AP2200]
PACKAGE
0.60MAX
3.00±0.05
3.00±0.05
S
1
0.25±0.05
0.50
1.25±0.05
0.575±0.05
C0.05
S
1.80±0.05
0.05
M
0.10±0.05
0.05
0.25±0.05
0.30±0.05
Rev1.01
0.30±0.05
14
2012/10
AsahiKASEI
AKM confidential
[AP2200]
MARKING
2200
(2)
YWW A
(1)
Rev1.01
(3)
(4)
(5)
(1) Pin 1 Mark
(2) Part No. : 2200
(3) Year Code (last 1 digit, ex: “2” for year 2012)
(4) Week Code
(5) Management No.
15
2012/10
IMPORTANT NOTICE
 These products and their specifications are subject to change without notice.
When you consider any use or application of these products, please make inquiries the sales office
of Asahi Kasei Microdevices Corporation (AKM) or authorized distributors as to current status of the
products.
 Descriptions of external circuits, application circuits, software and other related information
contained in this document are provided only to illustrate the operation and application examples of
the semiconductor products. You are fully responsible for the incorporation of these external circuits,
application circuits, software and other related information in the design of your equipments. AKM
assumes no responsibility for any losses incurred by you or third parties arising from the use of
these information herein. AKM assumes no liability for infringement of any patent, intellectual
property, or other rights in the application or use of such information contained herein.
 Any export of these products, or devices or systems containing them, may require an export license
or other official approval under the law and regulations of the country of export pertaining to customs
and tariffs, currency exchange, or strategic materials.
 AKM products are neither intended nor authorized for use as critical componentsNote1) in any safety,
life support, or other hazard related device or systemNote2), and AKM assumes no responsibility for
such use, except for the use approved with the express written consent by Representative Director
of AKM. As used here:
Note1) A critical component is one whose failure to function or perform may reasonably be expected to result,
whether directly or indirectly, in the loss of the safety or effectiveness of the device or system containing it,
and which must therefore meet very high standards of performance and reliability.
Note2) A hazard related device or system is one designed or intended for life support or maintenance of
safety or for applications in medicine, aerospace, nuclear energy, or other fields, in which its failure to function
or perform may reasonably be expected to result in loss of life or in significant injury or damage to person or
property.
 It is the responsibility of the buyer or distributor of AKM products, who distributes, disposes of, or
otherwise places the product with a third party, to notify such third party in advance of the above
content and conditions, and the buyer or distributor agrees to assume any and all responsibility and
liability for and hold AKM harmless from any and all claims arising from the use of said product in the
absence of such notification.
Rev1.01
16
2012/10