Charge-Pump for White LED and Power Supply
RN5T651
Development Specifications
Rev. 3.4
2009.05.20
RICOH COMPANY, LTD.
Electronic Devices Company
This specification is subject to change without notice.
RN5T651 Charge-Pump for White LED and Power Supply
Table of Contents
1.
Outline......................................................................................................................................................... 3
2. Feature ........................................................................................................................................................ 3
3. Pin Configuration ........................................................................................................................................ 4
4. Block Diagram............................................................................................................................................. 5
5. Pin Description ............................................................................................................................................ 6
6. Functional Blocks ........................................................................................................................................ 7
6.1 Regulators ............................................................................................................................................. 7
6.1.1 LDO1 Electrical Characteristics ................................................................................................................7
6.1.2 LDO2 Electrical Characteristics ................................................................................................................8
6.2 Step-down DC/DC Converters ................................................................................................................ 9
6.2.1 Step-down DC/DC Converter Block Diagram...........................................................................................9
6.2.2 Output Voltage Setting Calculation Formula............................................................................................. 9
6.2.3 Step-down DC/DC Convertors Electrical Characteristics .......................................................................10
6.2.4 (Reference waveform) Soft-start Waveforms (simulation result) ............................................................10
6.3 Thermal Shutdown Circuit.................................................................................................................... 11
6.3.1 Thermal Shutdown Block Diagram ......................................................................................................... 11
6.3.2 Thermal Shutdown Explanation of Operation......................................................................................... 11
6.3.3 Thermal Shutdown Electrical Characteristics.......................................................................................... 11
6.4 Charge Pump ....................................................................................................................................... 12
6.4.1 Block Diagram......................................................................................................................................... 12
6.4.2 Operation ................................................................................................................................................. 13
6.4.3 Protection circuit......................................................................................................................................14
6.4.4 Unused DIN_ pin..................................................................................................................................... 14
6.4.5 Soft-start .................................................................................................................................................. 14
6.4.6 Charge Pump Electrical Characteristics................................................................................................... 15
6.4.7 STBB Logic Input ................................................................................................................................... 16
6.5 UVLO(Under Voltage Lock Out) .......................................................................................................... 16
6.6 CPU Interface...................................................................................................................................... 17
6.6.1 Start and Stop Condition.......................................................................................................................... 17
6.6.2 Data Transmission and its Acknowledge ................................................................................................. 18
6.6.3 I2C-Bus Slave Address............................................................................................................................ 18
©2009 Rev. 3.4 Page 1
RN5T651 Charge-Pump for White LED and Power Supply
6.6.4 Data Transmission Write Format ............................................................................................................. 19
6.6.5 Internal Register Write-in Timing............................................................................................................ 19
6.6.6 Connection of I2C-Bus............................................................................................................................ 20
6.6.7 AC Characteristics of I2C-Bus ................................................................................................................21
7. Register ..................................................................................................................................................... 22
7.1 Register Map ....................................................................................................................................... 22
7.2 Main / Sub / Flash / Strobe Luminance .................................................................................................. 23
7.3 LDO1 / LDO2 Output Voltage ..............................................................................................................24
7.4 Buck Enable ........................................................................................................................................ 24
7.5 Others Function ................................................................................................................................... 25
8. Electrical Characteristics ........................................................................................................................... 26
8.1 Absolute Maximum Ratings.................................................................................................................. 26
8.2 Recommendation of Operation Conditions .............................................................................................26
8.3 General Characteristics......................................................................................................................... 26
8.4 DC Characteristics ...............................................................................................................................27
9. Additional Application Circuit................................................................................................................... 28
10. Package Information.............................................................................................................................. 30
©2009 Rev. 3.4 Page 2
RN5T651 Charge-Pump for White LED and Power Supply
1. Outline
RN5T651 contains constant frequency charge pump to optimize for white LED application, step-down DC/DC
converter and two low-noise LDOs. Output enable/disable, LEDs current setting and LDO output voltage setting
are individually controllable through I2C.
2. Feature
z Power Supply Function
9 Step-down DC/DC converter × 1 (ON/OFF programmable)
9 LDO × 2 (ON/OFF programmable)
9 Over current Protection (ALL Regulators) and thermal shutdown
z White LED Charge Pump
9 Current capability: All currents capability 450mA
9 Flash at 300mA max.
9 Four Main LEDs at 25mA max.
9 Two Sub LEDs 25mA max.
I2C-Bus (Max 400kHz)
z
9 Address = 12h
9 ON/OFF control
9 Individual LEDs current value setting
9 Individual LDOs voltage value setting
z Others
9 Soft-start circuit
9 Short-circuit circuit, open-circuit and Thermal Protection
z Package
9 28pin Thin QFN package (Body size: 4 x 4 x 0.8mm)
z Process
9 CMOS process
©2009 Rev. 3.4 Page 3
RN5T651 Charge-Pump for White LED and Power Supply
3. Pin Configuration
(TOP VIEW)
DIN3
DIN2
DIN1
VOUT
C1P
C2P
C2M
GND1
DIN5
DIN4
28
27
26
DIN6
25
1
2
3
4
RN5T651
5
6
7
10
C1M
VIN1
11
VEN
9
8
PGND1
GND2
DIN7
24
23
13
12
SCL
STBB
VREF
22
14
SDA
LDOUT1
21
VIN3
20
LDOUT2
19
FB
18
PGND2
17
LX
16
VIN2
15
QFN0404-28 pin
Pin No. Name Pin No. Name Pin No. Name Pin No. Name
1 DIN3 8 PGND1 15 VIN2 22 VREF
2 DIN2 9 C1M 16 LX 23 GND2
3 DIN1 10 VIN1 17 PGND2 24 DIN7
4 VOUT 11 VEN 18 FB 25 DIN6
5 C1P 12 STBB 19 LDOUT2 26 DIN5
6 C2P 13 SCL 20 VIN3 27 GND1
7 C2M 14 SDA 21 LDOUT1 28 DIN4
Fig 3-1 Pin Configuration
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RN5T651 Charge-Pump for White LED and Power Supply
4. Block Diagram
VIN2
LX
V CORE
@500mA
4.7uF
2.2uH
FB
DC/DC
Step-down
(@500mA)
Charge Pump
@450mA
VIN1
C2P
1uF
C2M
C1P
1uF
C1M
VOUT
2.2uF
PGND1
4.7uF
GND
GND GND
LDOUT1
LDOUT2
PGND2
VIN3
VREF
GND2
VEN
SCL
SDA
STBB
VREF
LDO1
LDO2
UVLO
Digital
Thermal Shutdown
CC Driver
(Main)
5bit DAC
CC Driver (Sub)
5bit DAC
CC Driver (Flash)
5bit DAC
Fig 4-1 Block Diagram
DIN1
@25mA
DIN2
@25mA
DIN3
@25mA
DIN4
@25mA
DIN5
@25mA
DIN6
@25mA
DIN7
@300mA
GND1
GND
©2009 Rev. 3.4 Page 5
RN5T651 Charge-Pump for White LED and Power Supply
5. Pin Description
No. Name I/O
1 DIN3 O LED driver current control output 3
2 DIN2 O LED driver current control output 2
3 DIN1 O LED driver current control output 1
4 VOUT O LED driver voltage output
5 C1P - Charge pump boost capacitor connection
6 C2P - Charge pump boost capacitor connection
7 C2M - Charge pump boost capacitor connection
8 PGND1 - Ground (charge pump)
9 C1M - Charge pump boost capacitor connection
10 VIN1 - Power supply (charge pump)
11 VEN - Voltage supply (I2C), enable input
12 STBB I Strobe enable input
13 SCL I I2C interface clock input
14 SDA I/O I2C interface data input
15 VIN2 - Power supply (DC/DC convertor)
16 LX O DC/DC convertor inductor switching pin
17 PGND2 - Ground (DC/DC convertor)
18 FB I DC/DC convertor feed back pin
19 LDOUT2 O LDO2 output
20 VIN3 - Power supply
21 LDOUT1 O LDO1 output
22 VREF O Bypass capacitor connecting pin
23 GND2 - Ground
24 DIN7 O LED driver current control output 7
25 DIN6 O LED driver current control output 6
26 DIN5 O LED driver current control output 5
27 GND1 - Ground
28 DIN4 O LED driver current control output 4
Function Notes
Table 5-1 Pin Description
©2009 Rev. 3.4 Page 6
RN5T651 Charge-Pump for White LED and Power Supply
6. Functional Blocks
6.1 Regulators
6.1.1 LDO1 Electrical Characteristics
Operating Conditions (unless otherwise specified) V
BATT
= 3.6V, C
= 1μF, Ta = 25℃
REFO
Symbol Item Condition Min Typ Max Units
VOUT1 Output Voltage
50μA＜IOUT1＜300mA
VOUT1+0.5V≦V
BATT
(VIN)≦4.5V
-2% 1.50 +2% V
IOUT1 Output Current - 300 mA
ILIM1 Current Limit VOUT1=POUT1－0.2V 500 mA
VDRP1 Drop-out Voltage IOUT1=200mA, Ta =85℃ 200 mV
ΔVOUT1
ΔVIN
ΔVOUT1
ΔIOUT1
ΔVOUT1
ΔT
a
Line Regulation
Load Regulation 50μA＜IOUT1＜300mA 25 mV
Output Voltage
Temperature
Coefficient
RR1 Ripple Rejection
EN1
Output Noise
(RMS)
VOUT1+0.5V≦V
BATT
IOUT1=150mA
-40℃≦T
≦85℃ +100 ppm/℃
a
f=10Hz-10kHz, C
IOUT1=30mA
BW=100Hz-100kHz, C
IOUT1=30mA
(VIN)≦4.5V
=2.2μF
out
=2.2μF
out
2.4 mV
60 dB
35
μVrm s
BC1 Bypass Capacitor 0μA＜IOUT1＜300mA 2.2 μF
ISS1 Supply Current
Normal (IOUT1=Max) 50 *1
OFF 1
μA
1.50
1.80
2.50
2.60
2.80
3.00
3.10
3.30
1.85 *
+2% V
POUT1
Programmable
Output Voltage
IOUT1=300mA -2%
2.40 *
2.55 *
2.70 *
2.85 *
2.90 *
3.20 *
Table 6-1 LDO1 Electrical Characteristics
Note*: Bypass capacitor: 2.2
μF, in mounted state.
For optimized phase compensation, the bypass capacitor must be the ceramic type.
©2009 Rev. 3.4 Page 7
RN5T651 Charge-Pump for White LED and Power Supply
6.1.2 LDO2 Electrical Characteristics
Operating Conditions (unless otherwise specified) V
BATT
= 3.6V, C
= 1μF, Ta = 25℃
REFO
Symbol Item Condition Min Typ Max Units
VOUT2 Output Voltage
50μA＜IOUT2＜300mA
VOUT2+0.5V≦V
BATT
(VIN)≦4.5V
-2% 1.50 +2% V
IOUT21 Output Current - 300 mA
ILIM2 Current Limit VOUT1=POUT1－0.2V 500 mA
VDRP2 Drop-out Voltage IOUT2=200mA, Ta =85℃ 200 mV
ΔVOUT2
ΔVIN
ΔVOUT2
ΔIOUT2
ΔVOUT2
ΔT
a
Line Regulation
Load Regulation 50μA＜IOUT2＜300mA 25 mV
Output Voltage
Temperature
Coefficient
RR2 Ripple Rejection
EN2
Output Noise
(RMS)
VOUT2+0.5V≦V
BATT
IOUT2=150mA
-40℃≦T
≦85℃ +100 ppm/℃
a
f=10Hz-10kHz, C
IOUT2=30mA
BW=100Hz-100kHz, C
IOUT1=30mA
(VIN)≦4.5V
=2.2μF
out
=2.2μF
out
2.4 mV
60 dB
35
μVrm s
BC2 Bypass Capacitor 0μA＜IOUT2＜300mA 2.2 μF
ISS2 Supply Current
Normal (IOUT2=Max) 50 *1
OFF 1
μA
1.50
1.80
2.50
2.60
2.80
3.00
3.10
3.30
1.85 *
+2% V
POUT2
Programmable
Output Voltage
IOUT2=300mA -2%
2.40 *
2.55 *
2.70 *
2.85 *
2.90 *
3.20 *
Table 6-2 LDO2 Electrical Characteristics
Note*: Bypass capacitor: 2.2
For optimized phase compensation, the bypass capacitor must be ceramic type.
μF, in mounted state.
Note*1: Vref Block Supply Current typ 20μA
ex)LDO1+LDO2+Vref =120μA(typ)
LDO1+Vref=70μA(typ)
©2009 Rev. 3.4 Page 8
RN5T651 Charge-Pump for White LED and Power Supply
6.2 Step-down DC/DC Converters
(a) Output voltage
The output voltage is decided according to the resistance ratio of external resistor. Please refer to the formulas in
section 6.2.2 for the output voltage set.
(b) Additional components
It can be easily composed of DC/DC converters with only few kinds of external components such as inductor,
capacitor and etc. For the output capacitors, ceramic type is recommended for voltage ripple.
(d) Protection circuits
Max Duty circuit limits maximum pulse width of DC/DC. Current Limit circuit limits peak current of LX at clock
cycle of DC/DC. Latch type protection circuit starts working if the over-current condition keeps on for certain time.
Latch-type protection circuit latches an internal driver by keeping it disable. To release the protection condition,
enable it again after disabling DC/DC by setting
6.2.1 Step-down DC/DC Converter Block Diagram
Vref
Slope
Compansation
GND
Current
Sense
Current
Limit
Output
Control
Fig 6-1 Step-down DC/DC Converter Block Diagram
Buck Enable register through I2C.
FB
2.2μH
LX
4.7μF
(ceramic)
PGND2
GND GND
6.2.2 Output Voltage Setting Calculation Formula
©2009 Rev. 3.4 Page 9
RN5T651 Charge-Pump for White LED and Power Supply
6.2.3 Step-down DC/DC Convertors Electrical Characteristics
Operating Conditions (unless otherwise specified) V
BATT
= 3.6V, C
= 1μF, Ta = 25℃
REFO
Symbol Item Condition Min Typ Max Units
Vbat Input voltage - 2.7 4.5 V
Voutdc Output voltage range Vbat=3.6V
ΔVout/ΔTa
Output voltage temperature
coefficient
-40<Ta<85℃
1.2 ~
2.6
V *1
±50
ppm/℃
Fosc Switching frequency Vbat=3.6V 2.5 MHz
Iss Consumption current Vbat=3.6V no load 3.5 mA
Ilx Maximum output current1
VLx Limit current
Votr Output transition response
Vrip Output ripple voltage
Vbat =3.6V
PWM Mode
Vbat=3.2～4.5V
Vbat=3.6V
1→120mA@ΔT=1μs
Vbat=3.6V
Iout=300mA
500 mA
1000 mA
30 45 mV
5 15 mV
Tprot Protection delay time Vbat=3.6V 1.6 ms
Tris Rising time
Vbat=3.6V Cout=4.7μF
-40<Ta<85℃
100
μs
Ronnch Output Nch ON Resistance Vbat=3.6V 0.4 Ω
Ronpch Output Pch ON Resistance Vbat=3.6V 0.4 Ω
Isd Standby current - 0.1
μA
Table 6-3 Step-down DC/DC Converter Electrical Characteristics
Note*1: The output voltages are selectable in ranges 1.2 ~ 2.6V by trimming.
6.2.4 (Reference waveform) Soft-start Waveforms (simulation result)
20us
Warm Up
80us
Rising Time
Time
DC/DC Output Wave Form
Enable Internal Signal “L”:Active
©2009 Rev. 3.4 Page 10
RN5T651 Charge-Pump for White LED and Power Supply
6.3 Thermal Shutdown Circuit
The thermal shutdown circuit is consisted of two temperature detection circuits and an op-amp.
6.3.1 Thermal Shutdown Block Diagram
VIN
Temperature
Detection Circuit
Control Circuit
GND
Temperature
Detection Circuit
GND
To Power-on
Control Circuit
Fig 6-2 Thermal Shutdown Circuit Diagram
6.3.2 Thermal Shutdown Explanation of Operation
The overheat state can be detected by comparing the output voltages from two temperature detection circuits,
which have different temperature Characteristics. If the overheat state is detected, internal POWERSW signal will
fall down to “L”, and RN5T651 will turn off to protect itself from overheating. When VEN signal is “H (Enable),
the thermal shutdown function is effective.
6.3.3 Thermal Shutdown Electrical Characteristics
Operating Conditions (unless otherwise specified) V
BATT
= 3.6V, C
= 1μF, Ta = 25℃
REFO
Symbol Item Condition Min Typ Max Units
T
Detected Temperature - 150 ℃
DET
T
Return Temperature - 100 ℃
RET
ISS Supply Current - 10 20 μA
Table 6-4 Thermal Shutdown Electrical Characteristics
©2009 Rev. 3.4 Page 11
RN5T651 Charge-Pump for White LED and Power Supply
6.4 Charge Pump
RN5T651 charge pump drives up to six white LEDs and one strobe with regulated constant current for uniform
intensity.
6.4.1 Block Diagram
Fig 6-3 Charge Pump Circuit Diagram
©2009 Rev. 3.4 Page 12
RN5T651 Charge-Pump for White LED and Power Supply
6.4.2 Operation
Initial and 1x mode
When any channel is turned ON, charge pump output (VOUT) voltage becomes VIN1 voltage. In this time, Soft-start
prevents the inrush current. As a result, RN5T651 starts at 1x mode.
In 1x mode, the following relation is the condition to stay in 1x mode.
VOUT - Vf > 0.25V (1)
Here, VOUT and Vf mean output of Charge pump and forward voltage of white LED, respectively. 0.25V means mode
transition threshold, in case of setting at 25mA of Main or Sub.
1x or 1.5x transition
When the battery voltage decreases and DIN_ pin voltage becomes lower than 0.25V for 100us, RN5T651 starts
charge pump in 1.5x mode.
In 1.5x mode, the following relation is the condition to stay in 1.5x mode.
VOUT - Vf > 0.25V (2)
In 1.5x mode, CP is switched to 1x mode about every 1 sec for 100us and judge the mode whether 1x or 1.5x.
1.5x or 2x transition
When the battery voltage decreases furthermore, and DINx_ pin voltage goes down below 0.25V for 100us,
RN5T651 starts 2x mode from 1.5x mode. In 2x mode, CP is switched to 1.5x mode about every 1 sec for 100usec and
judge the mode whether 2x or 1.5x.
1x/1.5x/2x mode transition
Every 1 sec return to 1x Mode.
( Except Strobe and Torch)
Every 1 sec return to 1.5x Mode.
( Except Strobe and Torch)
Initial
VOUT Soft-start
1x Mode, LED On
1.5x Mode
2x Mode
VOUT = GND
Any Channel On
VOUT becomes VIN voltage.
VOUT = VIN - Ro*Iled
DIN_=VOUT -
Min. DIN_ lower than 0.25V.
VOUT = 1.5*VIN - Ro*Iled
DIN_=VOUT Vf
Min. DIN_ lower than 0.25V.
VOUT= 2*VIN - Ro*Iled
VOUT =2* VIN - Ro*Iled
DIN_=VOUT -
Vf
-
Vf
©2009 Rev. 3.4 Page 13
RN5T651 Charge-Pump for White LED and Power Supply
6.4.3 Protection circuit
When any DIN_ pin is floating or grounded, VOUT voltage is limited below protection voltage by gating on/off charge
pump. In case any LED fails as an open circuit, VOUT voltage is also limited. Besides, when VOUT is smaller than
approximately 1.2V, charge pump also stops.
6.4.4 Unused DIN_ pin
In case that there is any unused DIN_ pin, connect DIN_ to GND to avoid over voltage protection status.
6.4.5 Soft-start
When LEDs are turned ON, to prevent the inrush current, RN5T651 has Soft-start function. (The internal resistance
gradually increases, just after LEDs enabled.)
©2009 Rev. 3.4 Page 14
RN5T651 Charge-Pump for White LED and Power Supply
6.4.6 Charge Pump Electrical Characteristics
Unless otherwise specified, VIN=3.6V, Ta=25℃, C1=C2=1uF, Cout=2.2uF
Parameter Conditions Min Typ Max Units
Charge Pump
Operating Voltage VIN1 and VIN3 voltage 2.7 4.5 V
VOUT voltage (Over voltage) Repeat On and Off in 1.5x or 2x 4.8 V
Over voltage detection hysteresis - 0.1 V
Maximum Output current VIN1=3.6V, VOUT=4.2V 450 mA
1x mode 1 Ohm
Output resistance: Ro
1.5x mode 3 Ohm
2x mode 5 Ohm
Switching Frequency - 1.25 MHz
Soft-start time - 0.12 msec
Supply current
1x mode, No load, (DET, Reference ON) 0.5 mA
1.5x mode or 2x mode 5 6 mA
Standby supply current VEN=0V, VIN1 and VIN3 current 1 uA
Current Limit VOUT shorted 50 mA
LED Driver
Maximum Sink current
DIN1-6 25 mA
DIN7 300 mA
LED current accuracy (Main, Sub) Code=1F, DIN_=0.25V -5 5 %
LED current accuracy (Flash) Code=1F, DIN7=0.4V -5 5 %
LED current matching Main or Sub, respectively. *1 -5 5 %
1x to 1.5x, 1.5x to 2x transition threshold At lowest DINx pin, DIN1-6 250 mV
1x to 1.5x, 1.5x to 2x transition threshold At lowest DINx pin, DIN7 400 mV
1x to 1.5x, 1.5x to 2x transition time Chattering noise reduction 100 us
DIN1-7 leakage in shutdown - 0.01 uA
Table 6-5 Charge Pump Electrical Characteristics
Note*1: Matching is defined (Iave_ - Iled_) / Iave_. Iave_ means the average current of Main or Sub, respectively.
Matching is defined without Vf voltage difference between channels.
For Main, Iave_main = (Iled1 + Iled2 + Iled3 + Iled4) / 4
For Sub, Iave_sub = (Iled5 + Iled6) / 2
©2009 Rev. 3.4 Page 15
RN5T651 Charge-Pump for White LED and Power Supply
6.4.7 STBB Logic Input
STBB input is used to control the flash LEDs without accessing I2C. When STBB is driven to "L", the flash LEDs are
driven by the current set in Strobe Luminance register. Driving STBB low overrides the flash LEDs set by I2C. With
STBB high, the flash LEDs becomes controllable by I2C.
Selecttor
Flash Luminance
SCL
SDA
STBB
Strobe Luminance
1
DAC<Resister>
0
Constant Current Pin
Enable
DIN7 Enable
6.5 UVLO(Under Voltage Lock Out)
Operating Conditions (unless otherwise specified) C
Symbol Parameter Condition Min Ty p Max Units
V
Under voltage lock out threshold VCCVIN rising 2.25 V
Release
V
Under voltage lock out threshold VCCVIN falling 2.05 2.20 2.35 V
Detect
V
UVLO Hysteresis - 50 mV
HYS
= 1μF, Ta = 25℃
REFO
DIN7
Table 6-6 UVLO Electrical Characteristics
©2009 Rev. 3.4 Page 16
RN5T651 Charge-Pump for White LED and Power Supply
6.6 CPU Interface
RN5T651 uses I2C -Bus system for CPU connection through 2-wires. Connection and transfer system of I2C -Bus
are described in the following sections.
6.6.1 Start and Stop Condition
Within the procedure of I2C, unique situations arise which are defined as Start and Stop conditions.
SCL
SDA
Fig 6-4 I2C -Bus Data Transmission
An “H” to “L” transition on SDA line while SCL is “H” indicates a Start condition. An “L” to “H” transition on
SDA line while SCL is “H” defines a Stop condition. Start and Stop conditions are always generated by master
(Refer to the figure below). The bus is considered to be busy after the start condition. The bus is considered to be
free again a certain time after the stop condition.
Start Condition Stop Condition
SCL
SDA
Fig 6-5 I2C-Bus Start and Stop Condition
©2009 Rev. 3.4 Page 17
RN5T651 Charge-Pump for White LED and Power Supply
6.6.2 Data Transmission and its Acknowledge
After start condition, data is transmitted by 1byte (8bits). The number of bytes that can be transmitted per
transmission is not limited. Receiver must send an acknowledge signal to the transmitter every time 8bit data is
transmitted.
Data transmission must be accompanied by acknowledge signal. The acknowledge-related clock pulse is generated
by the master. The transmitter releases SDA line during the acknowledge clock pulse.
The receiver must pull down SDA line during the acknowledge clock pulse so that it remains stable “L” during
“H” period of this clock pulse.
If a master–receiver is involved in a transfer, it must signal the end of the data to the slave-transmitter by not
generating an acknowledge signal on the last byte that was clocked out of the slave. The slave-transmitter must
release the data line to allow the master to generate a Stop condition.
SCL from
Master
SDA from
Transmitter
SDA
from
Receiver
Start Condition
12 89
Acknowledge Signal
Fig 6-6 I2C-Bus Data Transmission and its Acknowledge
6.6.3 I2C-Bus Slave Address
After Start condition, a slave address is sent. This address is 8 bits long followed by. The slave address of
RN5T651 are specified at “0001 0010b”
A7 A6 A5 A4 A3 A2 A1 A0
Setting
value
0 0 0 1 0 0 1 0
A7～A0: Slave Address
Fig 6-7 Slave Address of RN5T651
©2009 Rev. 3.4 Page 18
RN5T651 Charge-Pump for White LED and Power Supply
6.6.4 Data Transmission Write Format
The transmission format for the slave address allocated to each IC is defined by I2C-Bus standard. However
transmission method of address information of each IC is not defined. RN5T651 transmits data to the internal
address pointer at 1byte continue to the slave address and write command. For the data transmission, please
transmit MSB first from Master and following data in sequence. Also, Master should receive MSB first when it
receives data from the slave.
6.6.5 Internal Register Write-in Timing
SCL from Master
SDA from Master
SDA from Slave
An Internal Register
Write-in Signal (WRB)
Start Condition
198765423
Fig 6-8 Data Transmission Write Format
Acknowledge
Stop Condition
Writing to an internal register
Fig 6-9 Internal Register Write-in Timing
©2009 Rev. 3.4 Page 19
RN5T651 Charge-Pump for White LED and Power Supply
6.6.6 Connection of I2C-Bus
2 wires of SCL and SDA are connected to I2C-Bus and used for transmitting clock pulses and data individually.
All ICs connected to these two lines are designed not to be clamped, even though the voltage which exceeds its
power supply voltage is supplied through the input and output pins. Open drain pins are for output. This
construction allows the communication of signals between Ics, which have the different supply voltages, by adding
a pull-up resistor to each signal line as shown in the figure below. Each IC is designed not to give any effect on
SCL and SDA signal lines even though their power is turned off individually.
VDD1
V
DD2
V
DD3
V
DD4
SCL
SDA
R
P RP
Microcontroller RN5T651 Other Periphral IC
Fig 6-10 Connection of I2C-Bus
*1) For data interface, the following conditions must be met:
DD4 > VDD1
V
DD4 > VDD2
V
V
DD4 > VDD3
*2) When the master is one, the microcontroller is ready for driving
SCL to "H" and R
P of SCL may not be required.
©2009 Rev. 3.4 Page 20
RN5T651 Charge-Pump for White LED and Power Supply
6.6.7 AC Characteristics of I2C-Bus
Operating Conditions (unless otherwise specified) V
BATT
= 3.6V, C
= 1μF, Ta = 25℃
REFO
Symbol Item Condition Min Typ Max Units
f
SCL Clock Frequency - 400 kHz
SCL
t
BUF
t
SCL Clock “L” Time - 1.3 μs
LOW
t
SCL Clock “H” Time - 0.6 μs
HIGH
t
Start Condition Setup Time - 0.6 μs
SU;STA
t
Start Condition Hold Time - 0.6 μs
HD;STA
t
Stop Condition Setup Time - 0.6 μs
SU;STO
t
Data Hold Time - 0 μs
HD;DAT
t
Data Setup Time - 100*1 ns
SU;DAT
Bus Free Time Between
a Precedent and Start
- 4.7 μs
tR Rising Time of SCL and SDA (Input) - 300 ns
tF Falling Time of SCL and SDA (Input) - 300 ns
tSP
t
VENSET
t
VENHOLD
Spike Width that can be
Removed with Input Filter
VEN to Start Condition Setup Time - 100 μs
VEN to Stop Condition Hold Time - 100 μs
- 50 ns
Note*: All the above-mentioned values are corresponding to V
min and V
IH
max level.
IL
Note*1: Standard mode is allowed in I2C bus standard. For Standard mode, it needs to satisfy the condition;
tSU; DAT>=250ns.
t
BUF
t
HD;STA
t
VENSET
t
LOW
t
R
t
HD;DAT
t
HIGHtF
t
SU;DAT
t
SU;STA
t
HD;STA
t
SP
VEN
SDA
SCL
PS Sr P
Fig 6-11 AC Characteristics of I2C-Bus
t
VENHOLD
t
SU;STO
©2009 Rev. 3.4 Page 21
RN5T651 Charge-Pump for White LED and Power Supply
7. Register
7.1 Register Map
SDA Control Byte
Function
COMMAND DATA
C2 C1 C0 D4 D3 D2 D1 D0
Main Luminance 31-steps 25mA / LED max. 000 00000 = off
Initial value
Sub Luminance 31-steps 25mA / LED max. 001 00000 = off
Initial value
Flash Luminance 31-steps 300mA max,I2C enabled, 010 00000 = off
Initial value
Strobe Luminance 31-steps 300mA max, STBB enable, 011 00000 = off
Initial value
LDO1 Output Voltage x 16 steps
Initial value
LDO2 Output Voltage
Initial value
Buck Enable On / Off\ x x x x
Initial value
Others Function
Initial value
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
Enable
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
x
0 0 0 0 0
0 0 0 0 0
Main
0 0 0 0 0
Sub
Enable
DIN7
Enable
16 steps
LDO1
Enable
LDO2
Enable
Note*: C2 is MSB, and D0 is LSB.
Do not write “１”in Buck Enable Register [D3:D0].
Table 7-1 Register Map
©2009 Rev. 3.4 Page 22
RN5T651 Charge-Pump for White LED and Power Supply
7.2 Main / Sub / Flash / Strobe Luminance
Each sink current of DIN1-4, 5, 6, and 7 can be set by the code of D4-D0.
LED Current (mA) Data
Main Sub Flash Strobe D4 D3 D2 D1 D0
off off off off 0 0 0 0 0
0.8 0.8 9.7 9.7 0 0 0 0 1
1.6 1.6 19.4 19.4 0 0 0 1 0
2.4 2.4 29.0 29.0 0 0 0 1 1
3.2 3.2 38.7 38.7 0 0 1 0 0
4.0 4.0 48.4 48.4 0 0 1 0 1
4.8 4.8 58.1 58.1 0 0 1 1 0
5.6 5.6 67.7 67.7 0 0 1 1 1
6.5 6.5 77.4 77.4 0 1 0 0 0
7.3 7.3 87.1 87.1 0 1 0 0 1
8.1 8.1 96.8 96.8 0 1 0 1 0
8.9 8.9 106 106 0 1 0 1 1
9.7 9.7 116 116 0 1 1 0 0
10.5 10.5 126 126 0 1 1 0 1
11.3 11.3 135 135 0 1 1 1 0
12.1 12.1 145 145 0 1 1 1 1
12.9 12.9 155 155 1 0 0 0 0
13.7 13.7 165 165 1 0 0 0 1
14.5 14.5 174 174 1 0 0 1 0
15.3 15.3 184 184 1 0 0 1 1
16.1 16.1 194 194 1 0 1 0 0
16.9 16.9 203 203 1 0 1 0 1
17.7 17.7 213 213 1 0 1 1 0
18.5 18.5 223 223 1 0 1 1 1
19.4 19.4 232 232 1 1 0 0 0
20.2 20.2 242 242 1 1 0 0 1
21.0 21.0 252 252 1 1 0 1 0
21.8 21.8 261 261 1 1 0 1 1
22.6 22.6 271 271 1 1 1 0 0
23.4 23.4 281 281 1 1 1 0 1
24.2 24.2 290 290 1 1 1 1 0
25.0 25.0 300 300 1 1 1 1 1
Note*: Defaults are shown in Bold.
©2009 Rev. 3.4 Page 23
RN5T651 Charge-Pump for White LED and Power Supply
7.3 LDO1 / LDO2 Output Voltage
Each output voltage of LDO1 and LDO2 can be set by the code of D3-D0. And enable/disable of the output can be
individually set by D4 bit.
LDO Voltage (V) Data
LDO1 LDO2 D3 D2 D1 D0
1.50 1.50 0 0 0 0
1.80 1.80 0 0 0 1
2.50 2.50 0 0 1 0
2.60 2.60 0 0 1 1
2.80 2.80 0 1 0 0
3.00 3.00 0 1 0 1
3.10 3.10 0 1 1 0
3.30 3.30 0 1 1 1
1.85 1.85 1 0 0 0
2.40 2.40 1 0 0 1
2.55 2.55 1 0 1 0
2.70 2.70 1 0 1 1
2.85 2.85 1 1 0 0
2.90 2.90 1 1 0 1
3.20 3.20 1 1 1 0
1.50 1.50 1 1 1 1
7.4 Buck Enable
ON/OFF of DC/DC can be set by D4 bit.
Buck Enable (D4)
D4 Function
1 DC/DC convertor Output Enable
0 DC/DC convertor Output Disable
©2009 Rev. 3.4 Page 24
RN5T651 Charge-Pump for White LED and Power Supply
7.5 Others Function
Bit DATA Function
D4 Main Enable
D3 Sub Enable
D2 DIN7 Enable
D1 LDO1 Enable
D0 LDO2 Enable
1 Enable
0 Disable
1 Enable
0 Disable
1 Enable
0 Disable
1 Enable
0 Disable
1 Enable
0 Disable
Note*: The relations between each bit of the other function registers and each register are AND conditions.
©2009 Rev. 3.4 Page 25
RN5T651 Charge-Pump for White LED and Power Supply
8. Electrical Characteristics
8.1 Absolute Maximum Ratings
The operation exceeding “Absolute Maximum Ratings”below may cause permanent damage to the device.
The operation of the device within the stated ratings below is not guaranteed.
Symbol Item Condition Rated value Units
VIN1
VIN2
VIN3
VEN
ＶＩＮ Input Voltage Range All Input Pins -0.3～VEN+0.3 V
PD
T
Storage Temperature - -55～+125 ℃
stg
Power Supply Voltage Battery Voltage Input Pins -0.3～6.0 V
Package
Allowable Dissipation
Mounted on Board,
T
=70℃
a
1826 mW
8.2 Recommendation of Operation Conditions
Symbol Item Condition Min Typ Max Units
VIN Power Supply Voltage1 Battery Voltage Input Pins 2.7 3.6 4.5 V
VEN Power Supply Voltage - 1.8 3.0 4.2 V
Ta Temperature of Operation - -40 +85 ℃
8.3 General Characteristics
Symbol Item Condition Min Typ Max Units
ISSVEN VEN Supply Current SCL=SDA=STBB=VEN 1 μA
ISHUT
Shutdown Supply Current
(All output off)
VEN=3.0V, I2C ready,
TA=25℃
VEN=3.0V, I2C ready,
TA=85℃
VEN=0V, I2C off, TA=25℃ 1
VEN=0V, I2C off, TA=85℃
2.5
μA
©2009 Rev. 3.4 Page 26
RN5T651 Charge-Pump for White LED and Power Supply
8.4 DC Characteristics
Digital part Input
(Input Pin) SCL, SDA, STBB
Operating Conditions (unless otherwise specified) V
BATT
= 3.6V, C
= 1μF, Ta = 25℃
REFO
Symbol Item Condition Min Typ Max Units
VIH “H” Input Voltage -
VIL “L” Input Voltage -
VEN
x 0.7
V
VEN
x0.3
V
VOL “L” Output Voltage IOL=-3mA 0.3 V
IIL Input Leakage Current V=0～VEN -3 3 μA
IOZ Off Leakage Current V=0～VEN -3 3 μA
Terminal Equivalent Circuit
Fig 8-1 Terminal Equivalent Circuit
©2009 Rev. 3.4 Page 27
RN5T651 Charge-Pump for White LED and Power Supply
9. Additional Application Circuit
(1) Dual Main 4 LEDs and Sub 2 LEDs
(2) Mono 5 LEDs
Fig 9-1 Dual Main 4 LEDs and Sub 2 LEDs
Note*: Please connect DIN6 to GND.
Fig 9-2 Mono 5 LEDs
©2009 Rev. 3.4 Page 28
RN5T651 Charge-Pump for White LED and Power Supply
(3) Dual Main 3 LEDs and Sub 2 LEDs
Note*: Please connect DIN4 to GND.
(4)Mono 4 LEDs
Fig 9-3 Dual Main 3 LEDs and Sub 2 LEDs
Note*: When DIN5 and 6 are not used, write “0” into D3 of the other function registers or connect DIN5 and DIN6
to GND.
Fig 9-4 Mono 4 LEDs
©2009 Rev. 3.4 Page 29
RN5T651 Charge-Pump for White LED and Power Supply
10. Package Information
©2009 Rev. 3.4 Page 30
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