RICOH R1200x User Manual
R1200x Series
Σ
μ
PWM Step-up DC/DC Converter for PMOLED and General Use with shutdown function
The R1200x Series are CMOS-based PWM step-up DC/DC co nverters, which are optimized to drive passive matrix OLED or white
LEDs with constant current. The R1200x includes an under-voltage lockout circuit (UVLO), a soft-start circuit, and an over-voltage
protection circuit (OVP). By simply using an induc tor, divider resisters, and capacitors as external components, OLEDs and white
LEDs can be driven with high efficiently. At the standby mode, the internal NPN transistor can separate the output from the
input.(Shutdown function) By this shutdown function, white LED's current can be completely shutdown, and output voltage for OLED
can be completely cut off, therefore, the R1200x does not have bad impact on the life expectancy of OLED. The version with
auto-discharge function is available.
FEATURES
• Supply Current (IDD)························Typ. 500μA (VIN=5.5V,VFB=0V,Lx at no load)
• Standby Current (Istandby) ·················Max. 3μA (VIN=5.5V,CE="L")
• Input Voltage Range (VIN)···············2.3V to 5.5V
(Absolute maximum rating: 6.5V)
• Output Voltage Range (VOUT)··········Externally adjustable
• Feedback Voltage
(VFB)
··················1.0V
• Feedback Voltage Accuracy···········± 1.5%
•
Temp. Coeff. of Feedback Voltage
·······± 150ppm/°C
BLOCK DIAGRAMS
R1200xxxxA
(With Auto-Discharge function)
VFB VIN LX VOUT
R Q
S
OSC
Slope
Σ
UVLO
Switching
Control
Current
Protection
Current
Sense
Error Amp
PWM Comp
Vref
Soft Start
Compensation
OVP
Chip Enable
CE GND
V
V
FB
Vref
Soft Start
(Without Auto-Discharge function)
Error Amp
R1200xxxxB
PWM Comp
RQ
OSC
Slope
Compensation
SELECTION GUIDES
Halogen Free
Package
DFN1616-6 5,000 pcs
DFN(PLP)1820-6 5,000 pcs
SOT-23-6 3,000 pcs
Q'ty per Reel
Part No.
R1200L.xxx$ -TR
R1200K.xxx$ -TR
R1200N.xxx$ -TR-FE
PACKAGES (Top View) TYPICAL CHARACTERISTIC
DFN1616-6
6
1 CE
2 VFB
3 LX
4 GND
5 VIN
6 VOUT
)
The tab is substrate level (GND).
∗
APPLICATIONS
• OLED power supply for hand-held equipment • White LED driver for hand-held equipment
∗
3 4 2 5 1
DFN(PLP)1820-6
6 5 4
∗
1 2 3
1 CE
2 VFB
3 LX
4 GND
5 VIN
6 VOUT
SOT-23-6
6 5 4
1 2 3
1 CE
2 VOUT
3 VIN
4 LX
5 GND
6 VFB
• Oscillator Frequency (fosc)·············· Typ. 1.2MHz
•
Oscillator Maximum Duty Cycle (Maxduty)
··· Typ. 91%
• UVLO Detect Voltage (VUVLO1)········ Typ. 2.0V
• Coil-current Limit Circuit················· Current limit Typ. 700mA
• Over Voltage Protection Circuit (OVP)
• Soft Start Time
(t
start
)
······················· Typ. 1.5ms
• Packages······································· DFN1616-6, DFN(PLP)1820-6,
SOT-23-6
TYPICAL APPLICA TION
By simply using an inductor, divider resistors
and capacitors as external components, a
IN
S
.
xxx : Specify the OVP voltage.
L
X
UVLO
Switching
Control
Current
Current
Sense
Protection
.001.: OVP : 17V, .002.: OVP : 19V, .003.: OVP : 21V
OVP
Chip Enable
CEGND
V
OUT
.$. : Select from (.A.) with auto-discharge function or
(.B.) without auto-discharge function
R1200x Efficiency vs. Output Current
90
80
70
60
50
40
30
Efficiency η (%)
20
10
0
Output Current I
high-efficiency step-up DC/DC conver t er
can be easily configured.
C1
1μF
R1, R2 : For setting Output voltage
∗
R3 : 2kΩ, C3 : 220pF
V
IN
=3.6V Set V
LQH32CN220K53 (22μH)
LQH32CN100K53 (10μH)
LQH32CN4R7M53 (4.7μH)
L1
22μH
V
IN
CE
GND
OUT
=15V
0602040 80
OUT (mA)
L
X
V
OUT
V
FB
R2
R1
C3
C2
F
1
R3
No.EK-192-120323 Step-up DC/DC Converter
R1200x Series Step-up DC/DC Converter
PWM Step-up DC/DC Converter for PMOLED and General Use with shutdown function
Shutdown Function
Due to the typical step-up DC/DC converter circuit, a voltage
may appear at the output of the circuit even if the driver IC is in
the standby mode.
A current flows from the battery, through the inductor and diode
to the output pins. In case an OLED display is connected, it is
powered constantly and it may have an impact to the lifetime of
the OLED. In addition, when the input voltage is close to the Vf
voltage of a white LED, it is unable to turn these off properly.
The R120xx Series have an internal NPN transistor instead of
a diode. In standby mode, the NPN transistor turns off and
isolates the current flow from input to output.
The R1213K Series is able to shutdown that controls external
P-channel MOSFET by FLAG pin.
For OLED driver Step-up DC/DC Converter Comparison
Product Name
R1200x R1202xxxxA/B R1205x8xxA
Control PWM PWM PWM
Input Voltage Range 2.3V to 5.5V 2.3V to 5.5V 2.3V to 5.5V
Output Voltage Range Ext. adjustable (VFB=1.0V) Ext. adjustable (VFB=1.0V) Ext. adjustable (VFB=1.0V)
Feedback Voltage Accuracy
±1.5% ±1.5% ±1.5%
Oscillator Frequency 1.2MHz 1.2MHz 1.2MHz
Output Tr. Internal Internal Internal
Lx Current Limit Protection 700mA 350mA, 700mA 350mA, 700mA
UVLO Detector Threshold 2.0V 2.0V 2.0V
Soft-start Time
9 9 9
OVP Detector Threshold 17V, 19V, 21V 14V, 17V, 19V, 21V, 23V 25V
Package
Others
DFN1616-6,
DFN(PLP)1820-6,
SOT-23-6
Shutdown function
DFN1616-6B
TSOT-23-6
Shutdown function
Thermal shutdown circuit
V
IN
CE
GND
R1218x
L
X
V
OUT
V
FB
V
IN
CE
GND
OFF
R1200x
L
X
V
OUT
V
FB
DFN1616-6B
TSOT-23-6
Thermal shutdown circuit
The currently available information as of March 2012 is provided in this New Product News.
EK-192-120323
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