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OCP8110 datasheet Ver 1.2 20120704

OCP8110 datasheet Ver 1.2 20120704
OCP8110 datasheet Ver 1.2 20120704

DFN3030-10L (Top View)

Figure 1, Pin Assignments of OCP8110

General Description

The OCP8110 is current-regulated charge pump ideal for powering high brightness LEDs for camera

flash applications. The charge pump can be set to regulate two current levels for FLASH and TORCH modes. The OCP8110 automatically switches modes between step-up and step-down ensuring that LED current does not depend on the forward voltage. It

switches at 1.8MHz, allowing the use of tiny components. The supply voltage ranges from 2.7V to 5.5V and is ideally suited for all applications powered by a single Li_Ion battery cell or three to four NiCd, NiMH, or Alkaline battery cells.

The OCP8110 also features a very low shutdown current (less than 1uA), an automatic soft-start mode to

limit inrush current, as well as over current, over voltage and over temperature shutdown control. A Low current sense reference voltage (50mV) allows the user of small 0603 current sensing resistors. The OCP8110 is offered in Green 10-pin DFN

package and is specified over an ambient temperature range of -40?C to 85?C. Features

z Output Current up to 500mA at VIN=3.6V

z Up to 94% Efficiency in Torch Mode z Adjustable FLASH Mode Current

z Minimum External Components: No Inductors z Automatic Buck/Boost Mode Switchover z Wide V IN Range: 2.7V to 5.5V z High Frequency Operation: 1.8MHz

z 50mV Reference for low Loss Sensing z ISD < 1μA in Shutdown z PWM Dimming Control z Automatic Soft Start Limits Inrush Current z Over Voltage Protection on Output z Over Current Protection z Over Temperature Protection z Low Input and Output Ripple and Low EMI z Ultra-low Dropout Voltage in Buck Mode z Space Saving RoHS Compliant, Lead Free Package: 10-pin 3mm x 3mm DFN Applications

z White LED Torch/Flash for Cell Phones, DSCs, and Camcorders z White LED Backlighting z Generic Lighting/Flash/Strobe Applications z General Purpose High Current Boost Pin Configuration

Typical Application Circuit

Figure 2, Typical Application Circuit of OCP8110

500mA Buck/Boost Charge Pump LED Driver

Block Diagram

Figure 3, Block Diagram of OCP8110

Absolute Maximum Ratings1 (T A=25°C unless otherwise noted)

Parameter Symbol Rating Unit

Input Voltage V IN-0.3 to 6V

V EN ,I SET,V OUT Voltage

to

-0.3

V IN V Storage Temperature Range T S-55 to +150 ℃Operating Junction Temperature Range T J-40 to 150 ℃

Maximum Power Dissipation P D 1.9 W

Maximum Thermal Resistance θJA51 /W

ESD (HBM) ESD 4K V

Output Current Pulse (Flash) I OUT 1.0 A Output Current Continuous (Torch) I OUT 0.4 A

Recommended Operating Conditions (T

=25°C unless otherwise noted)

A

Parameter Symbol Conditions Rating Unit

Supply Voltage V IN Operating 2.7 ~ 5.5 V

+85 ℃Operating Temperature Range T A Operating -40

~

Electrical Characteristics

(Unless otherwise noted ,typical values are at T A =25, V ℃IN =3.6V, C FC =1uF, C OUT =10uF) Symbol Parameter Conditions Min. Typ. Max. Unit Input Power Supply V IN Input Voltage range 2.7 - 5.5 V I SD Shutdown Current EN=0V,Shutdown mode - 0.1 1 μA

I Q Quiescent Current

V IN = 2.7 - 5.5V, FLASH = GND,

1X Mode, I LOAD =100μA - 0.34 2 mA

FLASH = HIGH, 2X Mode - 1.75 - mA V FB FB Reference voltage

FLASH = GND 45 50 55 mV

FLASH = High, RSET = 53.6 k ?138 150 162 mV V FBR FB Reference Voltage Range

FLASH = High. Guaranteed by

design.

100 - 400 mV I FB FB Pin Current V FB = 0.3V - - 1 μA Charge Pump Section

R 2X Charge Pump Equivalent

Resistance (x2 mode) V FB = 0.0V, V IN = 3.6V - 4 - Ω

R 1X Charge Pump Equivalent

Resistance (x1 mode)

V IN = 3.6V - 0.4 0.7 Ω

T SS V OUT Turn-on Time VIN= 3.6V, FB within 90% of

regulation

- 140 250 μs

F OSC Switching Frequency - 1.8 - MHz V OUT Over-voltage Limit LED unconnected, V IN = 4.2V - 5.1 - V TSD Shutdown Temperature Temperature rising - 145 - ℃ TRT Recovery Temperature Temperature falling - 135 - ℃ ENABLE

V ENL Enable Threshold Low - - 0.4 V V ENH Enable Threshold High 1.4 - - V I LK EN, FLASH Pin Current - - 1 μA T FLASH Maximum Flash ON time FLASH = High 1.2 - 3.8 s

Typical Performance Characteristics:

(Unless otherwise noted ,T A =25, ℃V IN =3.6V, C IN =10uF, C FC =1uF, C OUT =10uF)

Figure 4, Output Current vs. Supply Voltage Figure 5, VFB vs. RSET Resistance

Figure 6, Flash 500mA Output Current vs. VIN Figure 7, Torch Output Current vs. VIN

Figure 8, Torch in 1X to Flash in 1X, VIN=4.2V Figure 9, Torch in 1X to Flash in 2X, VIN=3.6V

Figure 10, 250mA Torch, VIN=3.6V, VF=3.1V Figure 11, 250mA Torch, VIN=4.2V, VF=3.1V

Figure 12, 500mA Flash in 1X, VIN=4.2V, VF=3.1V Figure 13, 500mA Flash in 2X, VIN=3.6V, VF=3.1V

Figure 14, Start Up 500mA Flash, VIN=3.6V, VF=3.1V Figure 15, Start Up 500mA Flash, VIN=3.6V, VF=3.9V

Figure 16, Ripple Torch 250mA in 1X, VIN=4.2V Figure 17, Ripple Torch 250mA in 2X, VIN=3V

Figure 18, Ripple Flash 500mA in 2X Mode, VIN=3.6V Figure 19, Ripple Flash 500mA in 1X Mode, VIN=4.2V

Figure 20, Ripple Flash 500mA in 2X Mode, VIN=3.6V Figure 21, Ripple Flash 500mA in 1X Mode, VIN=4.2V

Figure 22, PWM Dimming, VIN=4.2 Figure 23, Over-Voltage Protection Waveform

Functional Description

The OCP8110 is a charge pump regulator designed for converting a Li-Ion battery voltage of 2.7V to 4.2V to drive a white LED used in digital still camera Flash and Torch applications. The OCP8110 has two modes of operation which are pin-selectable for either Flash or Torch. Flash mode is usually used with a pulse of about 200 to 300 milliseconds to generate a high intensity Flash. Torch can be used continuously at a lower output current than Flash and is often used for several seconds in a digital still camera “movie” mode.

The OCP8110 also has two modes of operation to control the output current: the 1 X mode and 2X mode. Operation begins after the enable pin EN receives a logic high, then OCP8110 goes through a soft-start mode designed to reduce inrush current. The OCP8110 starts in the 1X mode, which acts like a linear regulator to control the output current by continuously monitoring the feedback pin FB. In 1 X mode, if the OCP8110 auto detects a dropout condition, which is when the FB pin is below the regulation point for more than 64 cycles of the internal clock, the OCP8110 automatically switches to the 2X mode. The OCP8110 remains in the 2X mode until one of three things happens:

1) The enable pin EN has been toggled

2) The Flash pin has changed from high to low 3) VIN is cycled

The 2X mode is the charge pump mode where the output can be pumped as high as two times the input voltage, provided the output does not exceed the maximum voltage for the OCP8110, which is internally limited to about 5.1V. In the 2X mode, as in the 1 X mode, the output current is regulated by the voltage at the FB pin.

In the Torch mode, (Flash = GND) the Flash pin is set to logic low and the OCP8110 FB pin regulates to 50mV output:

V FB = 50mV (Torch Mode)

When in Flash mode, (Flash = VIN), the FB regulation voltage is set by the resistor R SET connected between the R SET pin and SGND and the equation:

5

*14SET

FB R uA V =

(Flash Mode)

Where 14μA is an internal regulated current and 5 is an internal factor used to scale the V SET voltage to the V FB voltage. Typical values of RSET are 140K ? to 35K ? for a range of V FB = 400mV to 100mV in Flash mode.

The output current is then set in either Flash or Torch mode by the equation:

SENSE

OUT R V I FB

=

FLASH Timeout Protection:

Due to the high currents typically available in Flash mode, it is necessary to protect the white LED from damage if left on too long. The OCP8110 has a timeout in Flash mode of about 1.2 seconds to 3.8 seconds after which it will shut down operation. Operation will not begin again in Flash mode until the Enable pin or Flash pin have been set Low and then High again.

Over-voltage Protection:

The OCP8110 has over voltage protection. If the output voltage rises above the 5.1V threshold, the over voltage protection shuts off all of the output switches to prevent the output voltage from rising further. When the output decreases below 5.1V, the device resumes normal operation.

Over-current Protection:

The over current protection circuitry monitors the average current out of the VOUT pin. If the average output current exceeds approximately 1 Amps, then the over current protection circuitry shuts off the output switches to protect the chip.

Brightness Control using PWM:

Dimming control can be achieved by applying a PWM control signal to the EN pin. The brightness of the white LEDs is controlled by increasing and decreasing the duty cycle of the PWM signal. While the operating frequency range of the PWM control is from 60Hz to 700Hz, the recommended maximum brightness frequency range of the PWM signal is from 60Hz to 200Hz. A repetition rate of at least 60Hz is required to prevent flicker.

Over-temperature Protection:

When the temperature of the OCP8110 rises above 145℃, the over temperature protection circuitry turns off the output switches to prevent damage to the device. If the temperature drops back down below 135 degrees Celsius, the part automatically recovers and executes a soft start cycle.

Ordering Information

Part Number Package Type Package Qty Temperature Eco Plan Lead

OCP8110VAD DFN3030-10L 13-in reel

3000pcs/reel

-40~85℃Green Cu Marking Information

DFN3030-10L

Package Information DFN3030-10L:

Symbol

Dimensions In Millimeters Dimensions In Inches Min. Nom. Max. Min. Nom. Max.

A 0.70 0.75 0.80 0.027

0.029 0.031 A1 0.00 - 0.05 0 - 0.002 A3 0.20 REF 0.008 REF

D 2.95 3.00 3.05 0.116

0.118 0.120

E 2.95 3.00 3.05 0.116

0.118 0.120

B 0.18 0.25 0.30 0.007

0.010 0.012 L 0.30 0.40 0.50 0.011

0.016 0.020 D2 2.30 2.45 2.55 0.091 0.096 0.100 E2 1.50 1.65 1.75 0.059

0.064 0.069

e 0.50 BSC 0.020 BSC

Packing Information

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