tb62731fug TOSHIBA Semiconductor CORPORATION, tb62731fug Datasheet

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tb62731fug

Manufacturer Part Number
tb62731fug
Description
Step-up Dc-dc Converter For White Led Driver
Manufacturer
TOSHIBA Semiconductor CORPORATION
Datasheet
Step-up DC-DC Converter for White LED Driver
efficiency step-up DC-DC converter. The converter turns on/off 2
to 6 white LEDs in series.
coil-switching and a function that reduces the LED current in
response to increase in temperature.
resistor.
crystal backlights for PDAs, cellular phones, and handy
terminals.
(Pb) -Free product.
Features
Pin assignment
The TB62731FUG is an LED driver that uses a high power
The IC incorporates an N-channel MOSFET transistor used for
The mean LED current can be easily set using an external
The IC is ideal as a driver for LED light sources used as liquid
The suffix (G) appended to the part number represents a Lead
Maximum output voltage: Vo ≤ 28 V
Mean LED current values set according to external resistor
Supply power: Up to 320 mW supported
Compact package: SSOP6-P-0.95B, 6 pins
Built-in temperature derating function: LED current derated automatically depending on temperature
High power efficiency
14 mA (typ.) @R_sens = 2.7 Ω
20 mA (typ.) @R_sens = 1.8 Ω
Up to 80% of peak power efficiency achieved using recommended components
Ron = 2.0 Ω (typ.) @V
Built-in low Ron power MOS switch
SHDN
GND
K
(top view)
TOSHIBA BiCD Digital Integrated Circuit Silicon Monolithic
IN
= 3.2~5.5 V
TB62731FUG
A
GND
V
CC
1
Weight: 0.016 g (typ.)
TB62731FUG
2006-06-14

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tb62731fug Summary of contents

Page 1

... TOSHIBA BiCD Digital Integrated Circuit Silicon Monolithic TB62731FUG Step-up DC-DC Converter for White LED Driver The TB62731FUG is an LED driver that uses a high power efficiency step-up DC-DC converter. The converter turns on/off white LEDs in series. The IC incorporates an N-channel MOSFET transistor used for coil-switching and a function that reduces the LED current in response to increase in temperature ...

Page 2

... Low, Standby Mode takes effect and pin A is turned off. Input pin for power supply for operating the IC Operating voltage range: 3.0~5.5 V DC-DC converter switch pin The switch is an N-channel MOSFET transistor. Note: Connect both GND pins to ground Buffer (sub) GND Function 2 TB62731FUG K 2006-06-14 ...

Page 3

... Test condition circuit ⎯ ⎯ ⎯ ⎯ ⎯ ⎯ ⎯ ⎯ tpw SHDN ⎯ OUT 3 TB62731FUG = 25°C) Unit °C/W °C °C °C = −40~85°C) T opr Min Typ. Max Unit ⎯ 3.0 4.3 V − V ⎯ CC ...

Page 4

... V (A) o ⎯ ⎯ I (A) o ⎯ ⎯ 3.2~4 ⎯ R_sens = 1.8 Ω 25°C T opr Equivalent to R_sens = 1.8 Ω, ⎯ Tdel L = 4.7 µ TB62731FUG = 3.0~5 Min Typ. Max Unit ⎯ 3.0 5.5 V ⎯ 0.6 0.9 mA ⎯ µA 0.5 1.0 ⎯ µA 4.2 7 ⎯ Ω 2.0 2.5 275 350 425 kHz ⎯ ...

Page 5

... STB IN REF Figure 1 Application Circuit The basic TB62731FUG circuit uses a step-up DC-DC converter and burst control of the current pulse. Basic Operation The internal MOS transistor (NMOS) is turned The inductance current IL increases from 0. When IL = ILpeak = 240 mA (typ.) or when 5/6 (83.3 350 kHz) is reached, the transistor is turned off. ...

Page 6

... Make sure the following condition for LED load between pins A and K is satisfied < LED Vf total IN CC Note that, regardless of control by the IC, LEDs are always on. Pulse stop time width: 7.5 µs (min)~15 µs (max) OSC Repetition of waveforms at left I A (peak) = 240 mA (typ.) is larger than the output power to the LED load. The IN 6 TB62731FUG 2006-06-14 ...

Page 7

... too large, it may not be possible for the current characteristic to be the specified value. Note that K > 1. min) × 2 × (1/Ip min × Ip min formula 2 OSC (mA), LED forward voltage: Vf LED (V), o × (1/η) × (1 formula (mA), and η > (%), then I o > = 3.12 V the input power TB62731FUG = 0.12 (mA result 2006-06-14 ...

Page 8

... Thus, 48.1 ( µ selected when the input voltage is low, 3.0 V. Note that the calculation does not consider fluctuations in inductance. Toshiba recommend selection of an inductance of 1.2 times the calculated value. The recommended inductance under the above conditions µ 48.1 ( µ H) × 1.2 > = 57.7 ( µ H (mA 1.1 o 43.8 ( µ TB62731FUG = 3 4 2006-06-14 ...

Page 9

... Relation between set current IO and setting resistance R_sens 9.1 8.2 6.8 5.6 4 (mA). o and output voltage V exceeds (typical value 25° (mA) 3.3 2.7 2.2 2 1.8 1.5 1.2 1 Resistance for setting current R_sens (Ω) Figure 4 9 TB62731FUG . The mean output current 320 (mW), mean current can be obtained. o 2006-06-14 ...

Page 10

... Output Derating Function Toshiba recommend derating the LED current depending on the increase in ambient temperature. The TB62731FUG is designed to ensure safe and efficient driving of white LEDs used as backlight sources for color LCDs. The IC incorporates a function that derates current according to the set temperature (the ambient temperature when the IC is mounted), Ta ...

Page 11

... Recommended LED current range (converted Figure 5 Derating Function of Set Current ( ° calculated as follows: ( ° calculated as follows 260 ( ° C/W) is the maximum value, θ Temperatures T (°C) and T (° TB62731FUG = 210~260 ( ° C/W) is used 100 2006-06-14 ...

Page 12

... V (V) CC Current consumption at shutdown I (SHDN) CC 0.5 0.4 0.3 0.2 0 3 (V) CC Output switching frequency 400 380 360 340 320 300 3 3 TB62731FUG 2 5.5 4 TB62731FUG TB62731FUG 1 2 5.5 12 TB62731FUG OSC 5 2006-06-14 ...

Page 13

... sens 60 1.8 Ω 3.2 3.4 Input voltage – power efficiency/mean current 100 sens 60 1.8 Ω 3.2 3.4 13 TB62731FUG η 3.6 3.8 4 4.2 Input voltage V ( η 3.6 3.8 4 4.2 Input voltage V ( η ...

Page 14

... R_sens 60 1.8 Ω 3.2 3.4 Input voltage – power efficiency/mean current 100 R_sens 60 1.8 Ω 3.2 3.4 14 TB62731FUG η 3.6 3.8 4 4.2 Input voltage V ( η 3.6 3.8 4 4.2 Input voltage V ( η ...

Page 15

... Input voltage – power efficiency/mean current 100 8 R_sens 60 5.1 Ω 3.2 3.4 3.6 Input voltage V Input voltage – power efficiency/mean current 100 8 R_sens 60 2.4 Ω 3.2 3.4 3.6 Input voltage V 15 TB62731FUG η 3.8 4 4.2 ( η 3.8 4 4.2 (V) IN 2006-06-14 ...

Page 16

... Package Dimensions Weight: 0.016 g (typ.) 16 TB62731FUG 2006-06-14 ...

Page 17

... Otherwise, the current or power consumption may exceed the absolute maximum rating, and exceeding the rating(s) may cause the device breakdown, damage or deterioration, and may result injury by explosion or combustion. In addition, do not use any device that is applied the current with inserting in the wrong orientation or incorrectly even just one time. 17 TB62731FUG 2006-06-14 ...

Page 18

... DC voltage will increase. If this output voltage is connected to a speaker with low input withstand voltage, overcurrent or IC failure can cause smoke or ignition. (The over current can cause smoke or ignition from the IC itself.) In particular, please pay attention when using a Bridge Tied Load (BTL) connection type IC that inputs output DC voltage to a speaker directly. 18 TB62731FUG 2006-06-14 ...

Page 19

... If the current sink capability of the power supply is small, the device’s motor power supply and output pins might be exposed to conditions beyond absolute maximum ratings. To avoid this problem, take the effect of back-EMF into consideration in system design. 19 TB62731FUG 2006-06-14 ...

Page 20

... TOSHIBA for any infringements of patents or other rights of the third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of TOSHIBA or others. 021023_C • The products described in this document are subject to the foreign exchange and foreign trade laws. 021023_D 021023_B 060106_Q 20 TB62731FUG 060116EBA 021023_E 2006-06-14 ...

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