SM8150A
PMIC with White LED Driver
1. OVERVIEW
The SM8150A is a charge pump type white LED driver, with 2-system programmable LDOs (Low Dropout
Regulator), and step-down DC/DC converter power management IC. The white LED driver provides constant-
current drive for 1 to 6 backlight white LED connected in parallel and 1 torch/strobe white LED. The charge
pump automatically selects between
×1
mode,
×1.5
boost mode, and
×2
boost mode in response to battery volt-
age, LED drive current, and VF
LED
(LED forward bias voltage drop) conditions in order to extend battery
drive life. The SM8150A operating mode settings are accessed using an I
2
C
*1
interface, allowing LED drive
current, LDO voltage, output ON/OFF, and other settings to be controlled from a microcontroller.
*1. I
2
C-BUS is a registered trademark of NXP B. V.
2. FEATURES
I
3. TYPICAL APPLICATION CIRCUIT
1µF
1µF
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Optimum specifications for clamshell cellular
phone with camera
• LCD backlight: Main-4ch/Sub-2ch (max 25mA/ch)
• Camera flash: 1ch (max 300mA)
Power saving design by automatic mode selection
of charge pump
• Power at
×
1.5 mode is reduced by 25% from
×
2 mode
• Power at
×1
mode is reduced by 50% from
×2
mode, 33% from
×1.5
mode
2
I C interface best match for cellular phone chipset
Selecting current value (torch/strobe) of flash LED
by SBN pin
Shutdown synchronized to microcontroller supply
by VEN pin
1 system of step-down DC/DC converter built-in
• Output: 1.2 to 3.0V@ max 500mA
2 systems of programmable LDO built-in
• Output: 1.5/1.8/2.5/2.6/2.8/3.0/3.1/3.3V@ max 300mA
Various protection circuits built-in
• Startup soft start circuit built-in
• Overtemperature thermal shutdown (TSD) cir-
cuit built-in
• Supply undervoltage lockout (UVLO) circuit built-in
Supply voltage range (VIN1 to VIN3): 2.7 to 4.6V
Logic operating voltage range (VEN) : 1.8 to 4.6V
White LED Driver
• Charge-pump frequency: 1.0MHz (typ)
• Charge-pump maximum output current: 450mA
• Backlight LED current: 25
±
1.5mA/ch (max)
• Backlight LED relative accuracy:
±
3%
• Flash LED current: 300
±
20mA (max)
DC/DC converter
• DC/DC converter output voltage: 1.2 to 3.0V (typ)
• DC/DC converter output current: 500mA (max)
• DC/DC converter operating frequency: 2.0MHz (typ)
• DC/DC converter voltage accuracy:
±
2%
LDO
• LDO output voltage: 1.5 to 3.3V (VIN = 3.6V)
• LDO output current: 300mA (max)
• LDO dropout voltage: 0.1V (typ)
• LDO voltage accuracy:
±
2%
Package: 28-pin QFN
3.6V
C1P
VIN1
4.7µF
PGND1
VIN2
2.2µF
PGND2
DIN2
VIN3
2.2µF
DIN3
DIN4
DIN5
DIN6
Logic supply
VEN
0.1µF
DIN1
C1M C2P
C2M
VOUT
2.2µF
SM8150A
DIN7
I
2
C
SCL
SDA
LDOUT1
2.2µF
LDOUT2
2.2µF
LDO1 output
LDO2 output
Strobe
ON/OFF
SBN
100kΩ
FB
8pF
VREF
LX
2.2µH
GND1
GND2
2.2µF
DCOUT
(1.8V)
200kΩ
0.1µF
4. APPLICATIONS
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Cellular phone
Mobile equipment
5. ORDERING INFORMATION
Device
SM8150AB
Package
28-pin QFN
SEIKO NPC CORPORATION —1
SM8150A
6. PINOUT
(Top view)
LDOUT1
VIN3
LDOUT2
FB
PGND2
LX
VIN2
VREF
GND2
DIN7
DIN6
DIN5
GND1
DIN4
21
22
15
14
28
1
7
8
SDA
SCL
SBN
VEN
VIN1
C1M
PGND1
7. PIN DESCRIPTION
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Name
DIN3
DIN2
DIN1
VOUT
C1P
C2P
C2M
PGND1
C1M
VIN1
VEN
SBN
SCL
SDA
VIN2
LX
PGND2
FB
LDOUT2
VIN3
LDOUT1
VREF
GND2
DIN7
DIN6
DIN5
GND1
DIN4
I/O
O
O
O
O
–
–
–
–
–
–
–
I
I
I/O
–
O
–
I
O
–
O
O
–
O
O
O
–
O
Description
LED drive current control output 3 (group A)
*1
LED drive current control output 2 (group A)
*1
LED drive current control output 1 (group A)
*1
LED drive voltage output
Charge pump boost capacitor connection
Charge pump boost capacitor connection
Charge pump boost capacitor connection
Ground (charge pump)
Charge pump boost capacitor connection
Supply input (charge pump)
Supply input (logic)
*2
Torch/strobe selecting voltage input (strobe when LOW)
*3
I
2
C interface clock input
*3
I
2
C interface data input
*3
Supply input (DC/DC converter)
DC/DC converter coil switching output
*4
Ground (DC/DC converter)
DC/DC converter feedback input
LDO output 2
*4
Supply input (logic and LDOs)
LDO output 1
*4
Bypass capacitor connection
Ground
LED drive current control output 7 (high-current LED)
*1
LED drive current control output 6 (group B)
*1
LED drive current control output 5 (group B)
*1
Ground
LED drive current control output 4 (group A)
*1
*1. Connect to ground when no LED is connected.
*2. Connect to a supply with
≥
1.8mA drive current capability. If pull-up resistors Rup are connected to SCL, SDA, and SBN, the current
consumption increases by the amount flowing through the pull-up resistances only. The current component for each of the 3 pins is
given by Iup [mA] = VEN [V] / Rup [kΩ].
*3. Pull-up or pull-down resistances are not built-in.
*4. Leave open circuit when not used (do not connect to ground).
SEIKO NPC CORPORATION —2
DIN3
DIN2
DIN1
VOUT
C1P
C2P
C2M
SM8150A
8. BLOCK DIAGRAM
VIN1
C1M C1P
C2M C2P
VIN2
VOUT
VIN3
Charge pump
1/ 1.5/ 2
DIN1
DIN2
Current control & Current detect
VEN
Group A
DIN3
DIN4
Group B
DIN5
DIN6
DIN7
GND2
OSC
VREF
Thermal
shutdown
UVLO
SCL
SDA
I
2
C
interface
&
Control
logic
Torch/
Strobe
Synchronous
step-down
DC/DC
converter
Programmable
LDO
Programmable
LDO
LX
FB
DCOUT
SBN
LDOUT1
LDOUT2
GND1
VREF
PGND1
PGND2
SEIKO NPC CORPORATION —3
SM8150A
9. ABSOLUTE MAXIMUM RATINGS
GND = PGND = 0V
Parameter
Supply voltage
Logic operating voltage
Input voltage
All other input pins
SDA
Output voltage
VOUT
All other output pins
VOUT
Output current
LX
LDOUT1 to 2
Power dissipation
Junction temperature
Storage temperature
−
Pins
VIN1 to 3
VEN
SBN, SCL, SDA
Symbol
V
IN
V
EN
V
DATA
V
INPUT
V
OUT_ACK
V
OUT_CP
V
OUTPUT
I
OUT_CP
I
OUT_LX
I
OUT_LDO
P
D
T
JMAX
T
STG
Rating
−0.3
to 5.5
−0.3
to 5.5
–0.3 to V
EN
+ 0.3
–0.3 to V
IN
+ 0.3
–0.3 to V
EN
+ 0.3
5.5
–0.3 to V
IN
+ 0.3
600
1.2
1
1.1 (θ
J
= 90°C /W)
*1
+125
−55
to +125
Unit
V
V
V
V
V
V
V
mA
A
A
W
°C
°C
*1. When the SM8150A is mounted on a 40
×
60
×
1.6mm 2-layer board whose wiring pattern ratio is 130%.
Note. The device may suffer breakdown if any one of these parameter ratings is exceeded.
The thermal resistance
θ
J
required for the operating environment is determined by the relationship with power
dissipation and operating temperature given below.
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Maximum junction temperature: T
JMAX
= 125 [°C]
Operating temperature: Ta [°C]
Thermal resistance:
θ
J
[°C/W]
P
D
=
(T
JMAX
−
Ta)
θ
J
2
1.5
P
D
[W]
1
0.5
0
0
25
50
Ta [°C]
75
85
θ
J
= 90°C/W
SM8150A power dissipation
SEIKO NPC CORPORATION —4
SM8150A
10. RECOMMENDED OPERATING CONDITIONS
VIN1 = VIN2 = VIN3, GND = PGND = 0V
Rating
Parameter
Pin
Symbol
V
IN_×1
Supply voltage
*1
VIN1 to 3
V
IN_×1.5
V
IN_×2
Logic operating voltage
Input voltage
Strobe time
*2
Torch LED current
*2
Operating temperature
DIN7
−
VEN
SBN, SCL,
SDA
V
EN
V
DATA
t
STROBE
I
LED7
Ta
I
LED7
≥
150mA
t
TORCH
>
250ms
Conditions
min
×1
mode, I
OUT
= 0mA
×1.5
mode, I
OUT
= 150mA
×2
mode, I
OUT
= 450mA
2.7
3.0
3.3
1.8
0
−
−
−30
typ
3.6
3.6
3.6
2.8
−
−
−
25
max
4.6
4.6
4.6
4.6
V
EN
250
150
+85
V
V
V
V
V
ms
mA
°C
Unit
*1. Supply voltage and I
OUT
(LED)
When the white LED drive current is increased, the required supply voltage also increases. The supply is automatically switched in charge pump boost
mode, and cannot be manually selected. The forward-bias voltage drop VF of the LED is assumed to be
≤
3.5V.
500
400
I
OUT
(LED) [mA]
300
200
100
0
2.5
3
3.5
4
4.5
5
V
IN
[V]
I
OUT
(LED) vs. V
IN
*2. Torch and Strobe
Pin DIN7 is provided for connection to a high-current white LED. Two types of light modulation (dimming) data are available, switched by the SBN input
voltage. When SBN is HIGH, torch mode is selected. When SBN is LOW, strobe mode is selected. The recommended operating condition is high cur-
rent with short ON times in strobe mode, and low current with longer ON times in torch mode. In strobe mode (SBN = LOW), high-current supply is the
main priority and, therefore, the current consumption is not optimized (see “Torch/Strobe Selecting”).
I
2
C data settings
DIN7
−
Enable
1
1
1
*
*
1
*
*
L
H
1
1
1
*
*
0
*
*
L
OFF
OFF
OFF
OFF
ON
OFF
Strobe
−
−
SBN
H
Torch
ON
Strobe
OFF
Dimming
Torch
Recommended operating conditions
I
LED7
<
150mA
Operating time
<
250ms
−
−
DIN7
−
Disable
SEIKO NPC CORPORATION —5
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