TB62752BFUG(O,EL);中文规格书,Datasheet资料

TOSHIBA BiCD Digital Integrated Circuit Silicon Monolithic

TB62752BFUG

Step Up Type DC/DC Converter for White LED

The TB62752BFUG is a high efficient Step-Up Type DC/DC Converter specially designed for constant current driving of White LED.

This IC can drive 2-7 white LEDs connected series using a Li-ion battery.

This IC contains N-ch MOS-FET Transistor for Coil-Switching, and LED current (IF) is set with an external resistor.

This IC is especially for driving back light white LEDs in LCD of PDA, Cellular Phone, or Handy Terminal Equipment. This device is Pb-free product.

Weight: 0.016 g (typ.)

Features

• 2-7 white LEDs connected series.

• Variable LED current IF is set with a external resistor: 20 mA (typ.) @RSENS = 15 Ω • Output power: Available for 800 mW LED loading (7LEDs, IF = Over 25 mA) • High efficiency: 80% over (using recommended external parts)

• Output over voltage shutdown function

: Switching operation is shut downed when OVD terminal voltage is over 37 V (typ.). • IC package: SSOP6-P-0.95B • Switching frequency: 1.0 MHz (typ.)

Pin Assignment (top view)

SHDN

16FB 󰌥OVD25GND VIN34SW

Note: This IC could be destroyed in some case if amounted in 180° inverse direction.

Please be careful about IC direction in mounting.

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TB62752BFUG Block Diagram

VIN

22 µHSWVIN DriverIsens COMP R QSOver voltage detection OVD ∑ 2.2 µH 1.0 µH C1 C2 Ramp generator 1.0 MHz oscillatorErrorAMP. SHDN 300 mV FB 15 Ω @20 mA Shutdown function GND

Pin Function

Pin No. Symbol Function Description Voltage-input terminal for IC-enable/disable LED-IF. A high input on this pin enables the IC to operate while a low input causes it to shut down. The behavior of the IC is unpredictable if the input on the pin is undefined. Ensure that the pin is tied to either a high or low level. 1 SHDN Over voltage detection terminal. 2 OVD IC switching operation is disabled with detection over voltage. If the voltage returns to detection level or less, operation is enabled again. 3 4 VIN SW Supply voltage input terminal. (2.8 V to 5.5 V) Switch terminal for DC/DC converter. Nch MOSFET built-In. 5 GND Ground terminal. 6 FB LED IF setting resistor connecting terminal.

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TB62752BFUG I/O Equivalent Pin Circuits

1. SHDN Terminal

VIN

2. OVD Terminal

OVD2SHDN1 3. VIN Terminal to GND Terminal

4. SW Terminal

SW4VIN3 GND5

5. FB Terminal

VIN

FB6

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TB62752BFUG Absolute Maximum Ratings (Ta = 25°C if without notice)

Characteristics Symbol Rating Unit Power supply voltage Input voltage Switching terminal voltage Switching terminal current Power dissipation VIN VIN (SHDN)VO (SW) IO (SW) PD −0.3 to + 6.0 V −0.3 to +VIN + 0.3 (Note 1)−0.3 to + 40 V V mA W 1500 0.41 (device) 0.47 (on PCB) (Note 2)300 (device) 260 (on PCB) −40 to + 85 −55 to + 150 Thermal resistance Operation temperature range Storage temperature range Maximum junction temperature Rth (j-a) Topr Tstg °C/W °C °C Tj 150 °C Note 1: Ensure that the supply voltage never exceeds 6.0 V.

Note 2: Power dissipation must be calculated with subtraction of 3.8 mW/°C from maximum rating with every 1°C if

Topr is upper 25°C. (on PCB)

Recommended Operating Condition (Ta = −40 to 85°C if without notice)

Tes

Characteristics Symbol Circuit

Power supply voltage LED current

VIN IF

⎯ ⎯

Test Condition Min Typ. MaxUnit

2.8 ⎯ 5.5 V VIN = 3.6 V, RSENS = 15 Ω 6 white LEDs, Ta = 25°C

⎯

20 ⎯ mA

Electrical Characteristics (Ta = 25°C, VIN = 2.8 to 5.5 V if without notice)

Tes Characteristics Symbol CircuitPower supply voltage Operating consumption current Quiescent consumption current SHDNterminal “H” level input voltage SHDNterminal “L” level input voltage SHDNterminal current Integrated MOS-Tr switching frequency Switching terminal leak current Test Condition Min Typ. MaxUnitVIN ⎯ 2.8 ⎯ 5.5 V ⎯ ⎯ IIN (ON) 1 VIN = 3.6 V, RSENS = 15 Ω IIN (OFF) 2 VIN = 3.6 V, VSHDN= 0 V VSHDNH VSHDNL 0.6 0.9 mA0.5 1.0 µA ⎯ ⎯ 3 3 ⎯ ⎯ 1.3 0 ⎯ VINV 0.4 V VIN = 3.6 V, I_SHDN 4 VSHDN= 3.6 V or 0 V fOSC 5 VIN = 3.6 V, VSHDN= 3.6 V Ioz (SW) 6 7 ⎯ 0 1.0 µA 1.0 1.43MHz0.77 ⎯ 0.5 1 µA mVmVFB terminal feedback voltage VFB 7 VIN = 3.6 V, RSENS = 15 Ω Ta = 25°C, L = 22 µH VIN = 4.2 V, RSENS = 150 Ω Ta = 25°C, L = 22 µH 285 300 315285 300 315−5 ⎯ ⎯ FB terminal line regulation FB terminal current OVD terminal detect voltage OVD terminal leakage current VIN = 3.6 V (typ.) ∆VFB 7 VIN = 3.0 to 5.0 V VIN = 3.6 V, IFB 8 VSHDN= 3.6 V, VFB = 300 mVVOVD 9 IOVD 10 VOVD = 30 V ⎯ 5 % ⎯ µA 0.02 29 31.5 34 V ⎯ 0.5 1 µA 4

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TB62752BFUG Usage Precautions

Protection in LED Opened Condition

The operation with OVD terminal is available for the protection in case LED circuit opened.

When the voltage of OVD terminal is over 37 V (typ.), Nch MOS switching operation is disabled in the IC. When the voltage of OVD terminal drops below 37 V (typ.), Nch MOS switching operation becomes available again.

If load of LED is detached, Nch MOS switching operation is disabled with detection of boost circuit voltage and the IC is protected from unexpected over voltage.

Setting of External Capacitor

Terminal for brightness control, recommended values are C1 = Over 2.2 (µF), C2 = Over 1.0 (µF)

The recommended values of the capacitors depend on the control of brightness. For details, please see the item “Control of brightness” from the next page.

These recommended values reduce fluctuation of input current to up accuracy of brightness.

Setting of IF

Resistance connects between RSENS pin and GND.

The average current is set by this RSENS value and average current are obtained by the following equation.

IF (mA) =

300 [mV]

RSENS [Ω]

Current value error is within ±5%.

Setting of External Inductor Size

Please select the inductor size with referring this table corresponding to each number of LEDs.

[Recommended inductor values]

LEDs Indictor Size 2 to 5 Over 6

10 µH 22 µH

Note

LED current IF = 20 mA

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TB62752BFUG Current Dimming Control

Recommended brightness control circuits are 4 types.

(1)

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• The recommended PWM signal frequency is from 100 Hz to 10 kHz. There is a possibility to arise the

audible frequency in mounting to the board because it is within the auditory area.

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• To reduce the fluctuation of input current and increase the accuracy of brightness, the values that

C1 = 4.7 (µF) or more, C2 = 0.1 (µF) or less are recommended. • When the PWM signal is off, the time to drain C2 of charge depends on the constant number. And so,

the actual value is little different from the theoretical value.

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• Set the amplitude of PWM signal within the range of SHDN terminal specification.

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• In case dimming by inputting the PWM signal to the SHDN terminal, this IC turns on and off

repeatedly.

And the rush current, which provides the charge to C2, arises in turning on. Take care in selecting the condenser.

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VIN = 2.8 to 5.5 V 22 µH S-Di Input PWM signal to SHDN terminal

IF can be adjusted with PWM signal by inputting it to SHDN terminal.

IF [mA] = 300 [mV] × ON Duty [%]

RSENS [Ω]

PWM signal C1 = 4.7 µF SHDNOVDFBGND

RSENS = 15 Ω C2 = 0.1 µF VINSW6

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TB62752BFUG (2)

Input analog voltage to FB terminal

IF can be adjusted with analog voltage input to FB terminal.

This method is without repeating IC ON/OFF, and no need to consider holding rash current. [Notice]

• LED current value goes over 100% of the current set with RSENS, if the input analog voltage is

between 0 V to 300 mV (typ.).

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VIN = 2.8to 5.5 V 22 µH S-Di

C1 = 2.2 µF SHDNOVDFB16 kΩRSENS = 15 Ω GND82 kΩAnalog voltage

(3)

Input PWM signal with filtering to FB terminal

IF can be adjusted with filtering PWM signal using RC filter indicated in recommended circuit, because the PWM signal can be regard as analog voltage after filtering.

This method is without repeating IC ON/OFF, and no need to consider holding rash current. [Notice]

• LED current value goes over 100% of the current set with RSENS, if the input voltage after filtering is

between 0 V to 300 mV (typ.).

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VIN = 2.8 to 5.5V 22 µH S-Di

C1 = 2.2 µF SHDNOVDFB16 kΩ82 kΩ0.1 µF10 kΩPWM signalRSENS = 15 Ω GND

C2 = 1.0 µF VINSWC2 = 1.0 µF VINSW7

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TB62752BFUG (4)

Input logic signal

IF can be adjusted with logic signal input as indicated in recommended circuit. The resistor connected the ON-State Nch MOS drain and RSENS determines IF.

Average of setting current IO (mA) is next, approximately.

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VIN = 2.8 to 5.5V 22 µH S-Di IF [mA] =

300 [mV]

Sum of resistor value [Ω]

C1 = 2.2 µF SHDNOVDFBGNDM1R1R2M2Logic signal

M1 M2 OFF OFF ON OFF OFF ON ON ON 300[mV]×LED Current 300 [mV] RSENS [Ω]300[mV]×RSENS[Ω]+R1[Ω]RSENS[Ω]×R1[Ω]RSENS[Ω]+R2[Ω]RSENS[Ω]×R2[Ω]300[mV]×RSENS[Ω]×R1[Ω]+RSENS[Ω]×R2[Ω]+R1[Ω]×R2[Ω]RSENS[Ω]×R1[Ω]×R2[Ω]

RSENS = 15 Ω C2 = 1.0 µF VINSW8

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TB62752BFUG TEST Circuit

1. IIN (ON)

6 FB 5 4 GND SW 6FB5GND4 SW 2. IIN (OFF)

TB62752BFUG SHDN OVD TB62752BFUG SHDNVIN 3 1 µF OVD23.6 V VIN 3 A 1 µF 1 µF 1 µF 1 3.6 V 2 13.6 V

3. VSHDNH, VSHDNL

6 FB 5 4 GND SW 4. ISHDN 6FB5GND4 SW TB62752BFUG SHDN OVD TB62752BFUG SHDNVIN 3 OVD21 0.4 → 1.3 V 3.6 V 2 10 V/3.6 V 1 µF 3.6 V 32 V 3.6 V A VIN 3

5. fOSC

F 1 kΩ 6 FB 5 4 GND SW 3.6 V 3.6 V A A6. IOZ (SW) A 6FB5GND4 SW TB62752BFUG SHDN OVD TB62752BFUG SHDNVIN 3 OVD2VIN 3 3.6 V 1 3.6 V 2.0 V 2 3.6 V 11 µF

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TB62752BFUG 7. VFB, ∆VFB*1

22 µH CRS04 A7 white LEDs 8. IFB

VIN = 3.6 V 3 VIN 2.2 µF 4 2 SW OVD 6FB1.0 µF GND SW TB62752BFUG SHDNTB62752BFUG SHDNGND FB 5 6 @20 mA 15 Ω OVD VIN 23.6 V 1 3.6 V 13 1 µF V

9. VOVD*1

22 µH CRS04 10. IOVD

VIN = 3.6 V 3 VIN 2.2 µF 4 2 SW OVD 1.0 µF 6FBV GND SW TB62752BFUG SHDNTB62752BFUG SHDNGND FB 5 6 OVD VIN 230 V 1 3.6 V 13 3.6 V 1 µF A*1: The locations of the pins differ from the actual ones to simplify the diagram. See page 1 for the actual pin

locations.

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TB62752BFUG(O,EL)