MP3307 Datasheet by Monolithic Power Systems Inc.

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MP3307

2.7V-5.5V Input, 24V OVP,

Programmable Fsw, White LED Driver

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The Future of Analog IC Technology

DESCRIPTION

The MP3307 is a non-synchronous WLED step-

up driver with a 2.7V to 5.5V input range. It

uses peak current mode to regulate the LED

current sensed through an external low-side

resistor.

The MP3307 features up to 2.2MHz of

programmable switching frequency, making it

easy to avoid noise interference, optimize

efficiency, and reduce the output filter

component size. To extend the dimming range,

both analog and PWM dimming modes are

supported with a separate input.

The MP3307 has LED open protection, output

over-voltage protection, cycle-by-cycle current-

limit protection, and thermal shutdown

protection.

The MP3307 is available in a TSOT23-8

package, which is ideal for use in video displays.

FEATURES

 2.7V to 5.5V Input Voltage

 Analog Dimming with >20kHz Input Signal

 Direct PWM Dimming Mode with 100Hz to

2kHz Input Signal

 Up to 2.2MHz Programmable Switching

Frequency

 Low 200mV Feedback Voltage with ±1%

Accuracy at Room Temperature

 24V Open-Load Protection Threshold

 UVLO and Thermal Shutdown

 Cycle-by-Cycle Over-Current Protection

 Available in a TSOT23-8 Package

APPLICATIONS

 Video Displays

 In-Car LCD Infotainment

 Tablets

All MPS parts are lead-free, halogen-free, and adhere to the RoHS directive. For

MPS green status, please visit the MPS website under Quality Assurance.

“MPS” and “The Future of Analog IC Technology” are registered trademarks of

Monolithic Power Systems, Inc.

TYPICAL APPLICATION

23 4 56

Effi_Boost

Effi_LEDs

MP5“ IANFY SW [3 VIN OVP E PWMH GND n EN/PWML F3 I] FREQ TJ

MP3307―2.7V-5.5V INPUT, 24V OVP, –PROGRAMMABLE FSW, WHITE LED DRIVER

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ORDERING INFORMATION

Part Number* Package Top Marking

MP3307GJ TSOT23-8

See Below

* For Tape & Reel, add suffix –Z (e.g. MP3307GJ–Z)

TOP MARKING

ANF: Product code of MP3307GJ

Y: Year code

PACKAGE REFERENCE

TOP VIEW

TSOT23-8

ABSOLUTE MAXIMUM RATINGS (1)

VIN ...................................................-0.3V to +6V

VSW, VOUT…………………………..…-1V to +40V

All other pins ..................................–0.3V to +6V

Junction temperature ................................150°C

Lead temperature .....................................260°C

Continuous power dissipation .....(TA = 25°C) (2)

TSOT23-8 ................................................ 1.25W

Recommended Operating Conditions (3)

Supply voltage (VIN) ........................2.7V to 5.5V

Operating junction temp. (TJ). .. -40°C to +125°C

Thermal Resistance (4) θJA θJC

TSOT23-8............................. 100...... 55 °C/W

NOTES:

1) Exceeding these ratings may damage the device.

2) The maximum allowable power dissipation is a function of the

maximum junction temperature TJ (MAX), the junction-to-

ambient thermal resistance JA, and the ambient temperature

TA. The maximum allowable continuous power dissipation at

any ambient temperature is calculated by PD (MAX) = (TJ

(MAX)-TA)/JA. Exceeding the maximum allowable powe

dissipation will cause an excessive die temperature, causing

the regulator to go into thermal shutdown. Internal thermal

shutdown circuitry protects the device from permanent

damage.

3) The device is not guaranteed to function outside of its

operating conditions.

4) Measured on JESD51-7, 4-layer PCB.

MP5“

MP3307―2.7V-5.5V INPUT, 24V OVP, –PROGRAMMABLE FSW, WHITE LED DRIVER

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ELECTRICAL CHARACTERISTICS

VIN = 3.6V, VEN = VIN, TA = 25°C, unless otherwise noted.

Parameters Symbol Condition Min Typ Max Units

Step-Up Converter

Operating input voltage VIN 2.7 5.5 V

Supply current (quiescent) IQ No load with switching 440 A

Supply current (shutdown) IST V

EN = 0V, VIN = 3.6V 1 A

Input UVLO threshold VIN_UVLO Rising edge 2.5 V

Input UVLO hysteresis 200 mV

EN high voltage VEN_HIGH V

EN rising 1.2 V

EN low voltage VEN_LOW V

EN falling 0.4 V

Switching frequency fSW R

OSC = 51k 2.22 MHz

Maximum duty cycle DMAX 90 93 %

Feedback regulation voltage VREF 198 200 202 mV

VREF ramp-up time per step tSTEP 320

s

Power Switch

Main switch on resistance RDSON_M V

IN = 3.6V 0.3 0.5 

Current Dimming

PWMH input low threshold VPWM_LO V

PWM falling 0.4 V

PWMH input high threshold VPWM_HI V

PWM rising 1.2 V

PWML shutdown time tSD EN/PWML high to low 20 ms

Protection

OVP 22.5 24 25.5 V

OVP voltage VOVP Hysteresis 2 V

Cycle-by-cycle current limit ILIM 1.6 A

OVP UVLO threshold VOVP_UV 1.25 V

Thermal shutdown threshold tST 150 °C

Thermal shutdown hysteresis 25 °C

I'III‘E' PWM Dimming Curve Analog Dimming Curve ‘LED (MA) ‘LED (MA) DUTY DUTY

MP3307―2.7V-5.5V INPUT, 24V OVP, –PROGRAMMABLE FSW, WHITE LED DRIVER

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TYPICAL PERFORMANCE CHARACTERISTICS

VIN = 3.6V, 3s*4p LEDs, L = 3.3µH, fs = 2.2MHz, TA = 25°C, unless otherwise noted.

0 0.2 0.4 0.6 0.8 1

I'I'II'S‘ Steady state Vm Power On VIN Power Off Lem ’, mm Dunn—n:— a ZODns/div Ams/div mums/div EN Power On EN Power Off PWM Dimming FPWM = zoon, D = 50% am 1‘1!- 4ms/uiv Ams/div 2msldiv Start-Up Open Load Thermal Shutdown in Open Load in Normal Operation then Recover st/div. 2ms/div zs/dw.

MP3307―2.7V-5.5V INPUT, 24V OVP, –PROGRAMMABLE FSW, WHITE LED DRIVER

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

VIN = 3.6V, 3s*4p LEDs, L = 3.3µH, fs = 2.2MHz, TA = 25°C, unless otherwise noted.

5V/div.

OUT

5V/div.

200mA/div.

LED

100mA/div.

5V/div.

200mA/div.

LED

100mA/div.

5V/div.

200mA/div.

LED

100mA/div.

5V/div.

200mA/div.

LED

100mA/div.

5V/div.

OUT

2V/div.

200mA/div.

LED

100mA/div.

5V/div.

OUT

2V/div.

200mA/div.

LED

100mA/div.

10V/div.

OUT

20V/div.

2A/div.

LED

100mA/div.

10V/div.

OUT

10V/div.

2A/div.

LED

100mA/div.

10V/div.

OUT

5V/div.

500mA/div.

LED

100mA/div.

I'I'IPS' me or EN/PWML PWM

MP3307―2.7V-5.5V INPUT, 24V OVP, –PROGRAMMABLE FSW, WHITE LED DRIVER

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PIN FUNCTIONS

Pin # Name Description

1 SW

Power switch node. SW is the drain of the internal low-side MOSFET. Connect the

power inductor between SW and VIN.

2 OVP

Over-voltage sensing.

3 GND

Ground.

4 FB

LED current feedback. FB regulates the voltage across the current-sense resistor

between FB and GND to 200mV.

5 FREQ

Switching frequency set. Connect a resistor between FREQ and GND to program

the converter switching frequency. Do NOT leave FREQ floating.

6 EN/PWML

PWM brightness control/enable. Apply a PWM signal for PWM dimming. The PWM

frequency is proportional to the LED current dimming ratio—a lower dimming

frequency results in a smaller dimming current. For most applications, use a frequency

range of 200Hz to 2kHz. A low-level signal longer than 20ms will shut down the IC.

7 PWMH

Analog dimming input. A >20kHz PWM signal is recommended if a PWM signal input

is being used for analog dimming.

8 VIN

Input supply. VIN provides power for internal power and the logic circuits. VIN must

be bypassed locally.

"1P5“ VIN O _L W FlL J— IN = SW = ‘ OVP EN BG&Loglc OVP ] Detect Control Um! osc FWM ENI Connol . PWML G E VREF&DPWM PWMH 07 )7 PWM if 1 GND Comparalor = FREQ 1 FB 4 {1* 080 II|—Iw~.

MP3307―2.7V-5.5V INPUT, 24V OVP, –PROGRAMMABLE FSW, WHITE LED DRIVER

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Figure 1: Functional Block Diagram

I'III'E‘

MP3307―2.7V-5.5V INPUT, 24V OVP, –PROGRAMMABLE FSW, WHITE LED DRIVER

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OPERATION

The MP3307 uses peak-current-mode control to

regulate the current through the WLED string.

At the start of each oscillator cycle, the control

circuit turns on the low-side MOSFET (LS-FET,

M1). A stabilizing ramp is added to the output of

the current sense amplifier, which feeds into the

positive input of the PWM comparator and

prevents sub-harmonic oscillations at duty

cycles greater than 50%. When the input of the

PWM comparator equals the output voltage of

the error amplifier, M1 turns off. The inductor

current then flows through the external Schottky

diode, which forces the inductor current to

decrease.

The voltage at the output of the error amplifier

is the amplified difference between the 200mV

reference voltage and the feedback voltage. If

the feedback voltage starts to drop, the output

of the error amplifier increases. This also

increases the current flowing through M1, the

power to the inductor, and the output power.

This method regulates the LED current

accurately.

System Start-Up

When enabled, the MP3307 checks safety

limits, including UVLO, over-temperature

protection (OTP), and over-current protection

(OCP). If all of the protection tests pass, the

chip then boosts the step-up converter with an

internal soft start. During the soft start, the

current reference increases from 0 to 200mV in

32 steps (320µs per step) to prevent a large

inrush current.

Dimming Control

The MP3307 provides two dimming methods:

PWM dimming and analog dimming mode.

For PWM dimming, apply a PWM signal to

EN/PWML. The LED current is then segmented

according to the PWM signal and the average

LED current. See Equation (1):

dimset DI  (1)

When the PWM signal is high, the converter

operates in normal mode. Conversely, when the

PWM amplitude is low, the converter stops

switching. If the PWM signal low-level time is

more than 20ms, the IC shuts down. Use a

100Hz to 2kHz PWM dimming frequency for

most dimming ratio requests.

For analog dimming, connect the PWM

dimming signal to PWMH. An internal RC filter

filters the PWM signal. The LED current

amplitude equals Iset×Ddim, where Ddim is the

PWM duty cycle, and Iset is the LED current

amplitude. Use a >20kHz PWM signal to

improve filtering performance.

Open-String Protection

The MP3307 monitors VOUT for open-string

protection. If the LED string is open, the

feedback voltage is lower than the reference

voltage. The COMP then rises and charges the

output capacitor until the VOUT reaches the

protection point (VOVP).

The IC stops switching when VOUT reaches the

OVP threshold; it resumes operation when VOUT

drops below the threshold.

Input Under-Voltage Protection

When VIN exceeds 2.5V, the converter starts to

charge the internal reference and provides

power to the internal control circuitry. There is

an UVLO hysteresis (approximately 200mV) as

VIN falls. The IC shuts down when the input

voltage drops below 2.3V.

Thermal Shutdown Protection

Thermal shutdown prevents the IC from

operating at exceedingly high temperatures.

When the die temperature exceeds the upper

threshold (TST), the IC shuts down; it resumes

normal operation when the die temperature

drops below the lower threshold. Typically, the

hysteresis is 25°C.

Where Ddim is the PWM duty cycle, and Iset is the

LED current amplitude.

I'III‘E‘

MP3307―2.7V-5.5V INPUT, 24V OVP, –PROGRAMMABLE FSW, WHITE LED DRIVER

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APPLICATION INFORMATION

Selecting the Switching Frequency

The switching frequency of the step-up

converter can be programmed from 300kHz to

1.2MHz. A resistor on OSC sets the internal

oscillator frequency for the step-up converter

with Equation (2):

OSC

120000

f(kHz)R(k)



 (2)

For instance, if ROSC=51k, then the switching

frequency is 2.35MHz.

Setting the LED Current

Set the LED current through the current-setting

resistor on FB using Equation (3):

REF

LED

V(V)

I(mA) 1000

R()



 (3)

For instance, if VREF=200mV, and RFB=10,

then the LED current is 20mA. Do NOT leave

FB floating.

Selecting the Input Capacitor

The input capacitor reduces the surge current

drawn from the input supply and the switching

noise from the device. The input capacitor

impedance at the switching frequency should

be less than the input source impedance to

prevent the high-frequency switching current

from passing through to the input. Use ceramic

capacitors with X5R or X7R dielectrics for their

low ESR and small temperature coefficients.

For most applications, use a 2.2µF to 10F

ceramic capacitor.

Selecting the Inductor

The MP3307 requires an inductor to boost its

output voltage. An inductor with a larger value

results in less ripple current; it also lowers both

the peak inductor current and stress on the

internal N-channel MOSFET. However, the

larger inductor is physically larger and has both

a higher series resistance and a lower

saturation current.

Choose an inductor that does not saturate

under the worst-case load conditions. Select a

minimum inductor value to ensure that the

boost converter works in continuous conduction

mode with high efficiency and good EMI

performance.

Calculate the required inductance value using

Equation (4) and Equation (5):

OUT

SW LOAD

V D

(

)

L 2 f I





 (4)

OUT

D1 V

 (5)

Where VIN and VOUT are the input and output

voltages, fSW is the switching frequency, ILOAD is

the LED load current, and  is the efficiency.

To avoid hitting the switching current limit for

peak current mode, the worst-case inductor

peak current should be less than 80% of the

current limit (ILIM).

Selecting the Output Capacitor

The output capacitor keeps the output voltage

ripple small and ensures feedback loop stability.

The output capacitor impedance must be low at

the switching frequency. Ceramic capacitors

with X7R dielectrics are recommended for their

low ESR characteristics. Selection must also

account for the capacitance’s dependence on

the voltage rating. With DC bias voltage, the

capacitor can lose as much as 50% of its

capacitance at its rated voltage rating. Leave a

sufficient voltage rating margin when selecting

the component.

A capacitance that is too low or too high causes

loop instability. For most applications, select a

capacitor in the range of 2.2µF to 10F.

PCB Layout Guidelines

Efficient PCB layout is critical for preventing

noise, limiting electromagnetic interference, and

achieving stable operation. For best results,

refer to Figure 2 and follow the guidelines below:

1. Minimize the loop consisting of the

MP3307’s internal low-side MOSFET,

external Schottky diode, and output

capacitor, as it contains a high-

frequency ripple current.

2. Place the input and output capacitors as

close to the IC as possible.

ij MP3307—2.7V-5.5V INPUT, 24v ovp, fs-PROGRAMMABLE, WHITE LED DRIVER D . W H J. «HI—- XXKKKK O O O KKA‘XKK n—1 i I KKKKKK III—’W»

MP3307―2.7V-5.5V INPUT, 24V OVP, fs-PROGRAMMABLE, WHITE LED DRIVER

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TYPICAL APPLICATION CIRCUITS

4.7µF/10V

MP3307

3.3µH

4.7µF

/25V

VIN

GND

PWM

PWMH

EN/PWML

GND

51kΩ

FREQ

3s*Np

OVP

Figure 2: Typical Application for 3s*Np LEDs

I'I'IPS‘ MP3307—2.7V-5.5V INPUT, 24V OVP, fs-PROGRAMMABLE, WHITE LED DRNER TOP VIEW Jm _ I EDA}? FRONT VIEW DETAIL “A" RECOMMENDED LAND PATTERN SIDE VIEW NOTE: 1) ALL DIMENSIONS ARE IN MILLIMETERS. a PACKAGE LENGTH DOES NOT INCLUDE MDLD FLASH. PHDTRUSION 0R GATE BURR. 3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH OR PRDTRUSION. 4) LEAD COPLANARITV (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.10 MILLIMETERS MAX. 5)JEDEC REFERENCE Is M0493. VARIATION BA. 5) DRAWING IS NOT TO SCALE. 7) FIN 1 Is LOWER LEFT Pm WHEN READING TOP MARK FROM LEFT TO RIGHT. (SEE EXAMPLE TOP MARK)

MP3307―2.7V-5.5V INPUT, 24V OVP, fs-PROGRAMMABLE, WHITE LED DRIVER

NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications.

Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS

products into any application. MPS will not assume any legal responsibility for any said applications.

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PACKAGE INFORMATION

TSOT23-8

FRONT VIEW

NOTE:

TOP VIEW RECOMMENDED LAND PATTERN

SEATING PLANE

SIDE VIEW

DETAIL ''A''

SEE DETAIL ''A''

IAAAA

PIN 1 ID

See note 7

EXAMPLE TOP

MARK

MP3307 Datasheet by Monolithic Power Systems Inc.

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