Datasheet MP3394SGS Specification

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Page 1

The Future of Analog IC Technology

MP3394S

Step-Up, 4-String

Max 200mA/String White LED Driver

DESCRIPTION

The MP3394S is a step-up controller with 4 current channels. It’s designed to drive WLED arrays for large-size LCD-panel backlighting applications. The MP3394S is flexible, and can expand the number of LED channels with 1 or 2 MP3394S in parallel operating from a single inductive power source.

The MP3394S uses an architecture of current – mode and fixed operation frequency The frequency is programmable by an external frequency-setting resistor. MP3394S drives an external MOSFET to boost up the output voltage from a 5V to 28V input supply. It regulates the current in each LED string to the programmed value set by an external currentsetting resistor.

The MP3394S applies 4 internal current sources for current balance. The current matching can achieve 2.5% regulation accuracy between strings. Its low regulation voltage on LED current sources reduces power loss and improves efficiency.

FEATURES

• 4-String, Max 200mA/String WLED Driver

• 5V to 28V Input Voltage Range

• 2.5% Current Matching Accuracy Between

Strings

• Programmable Switching Frequency

• PWM or DC Input Burst PWM Dimming

• Open and Short LED Protection

• Programmable Over-Voltage Protection

• Cascading Capability with a Single Power

Source

• Under-Voltage Lockout

• Thermal Shutdown

• TSSOP16EP, SOIC16 and SOIC20

Packages

APPLICATIONS

• Desktop LCD Flat Panel Displays

• Flat Panel Video Displays

• 2D/3D LCD TVs and Monitors

All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithi Power Systems, Inc.

An external PWM input signal or DC input signal controls PWM dimming. In DC-input dimming mode, the dimming PWM signal can be generated internally and the dimming frequency is programmed by an external setting capacitor.

TYPICAL APPLICATION

MP3394S

VIN

VCC

COMP

OSC

BOSC

DBRT

ISET

ISENSE

VIN

5V to 28V

Enable

DIMMING

VCC

BOSC

COMP

OSC

COMP

BOSC

SET

GATE

GND

OVP

LED1

LED2

LED3

LED4

OUT

SENSE

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MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

ORDERING INFORMATION

Part Number Package Top Marking

MP3394SGF* TSSOP16EP MP3394S

MP3394SGS** SOIC16 MP3394S

MP3394SGY*** SOIC20 MP3394S

*For Tape & Reel, add suffix –Z (eg. MP3394SGF–Z).

**For Tape & Reel, add suffix –Z (eg. MP3394SGS–Z).

***For Tape & Reel, add suffix –Z (eg. MP3394SGY–Z).

Contact Factory for TSSOP16EP Availability

PACKAGE REFERENCE

TOP VIEW

Exposed Pad

Connect to GND

VCC

VIN

LED1

LED2

LED3

COMP

DBRT

GND

OSC

ISET

BOSC

LED4

COMP

DBRT

GND

OSC

ISET

BOSC

LED4

TOP VIEW

COMP

VCC

VIN

LED1

LED2

LED3

DBRT

GND

OSC

ISET

BOSC

LED4

VCC

VIN

OVP

LED1

LED2

LED3

TSSOP16EP SOIC16 SOIC20

ABSOLUTE MAXIMUM RATINGS

(1)

VIN................................................-0.3V to +30V

............................................-0.5V to +6.8V

GATE

VCC .............................................-0.5V to +6.8V

LED1

to V

....................................-1V to +55V

LED4

All Other Pins...............................-0.3V to +6.3V

Continuous Power Dissipation (T

= 25°C)

(2)

TSSOP16EP........................................... 2.78 W

SOIC16 ................................................... 1.56 W

SOIC20 ……………………………………1.74W

Junction Temperature...............................150°C

Lead Temperature ....................................260°C

Storage Temperature.............. -65 °C to +150°C

Recommended Operating Conditions

(3)

Supply Voltage VIN............................. 5V to 28V

LED Current (Backlight) ........... 10mA to 180mA

Operating Junction Temp. (T

). -40°C to +125°C

Thermal Resistance

(4)

θJC

TSSOP16EP ...........................45 ...... 10 ... °C/W

SOIC16 ...................................80 ...... 35 ... °C/W

SOIC20 ...................................72 ...... 30 ...°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 T ambient thermal resistance 

. The maximum allowable continuous power dissipation at

any ambient temperature is calculated by P (MAX)-TA)/JA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will 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 operation conditions.

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

(MAX), the junction-to-

, and the ambient temperature

(MAX) = (T

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MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

ELECTRICAL CHARACTERISTICS

VIN =12V, VEN = 5V, TA = 25°C, unless otherwise noted.

Parameters Symbol Condition Min Typ Max Units

Operating Input Voltage VIN 5 28 V

=12V, VEN=5V, no load with

Supply Current (Quiescent) IQ

switching

Supply Current (Shutdown) IST VEN=0V, VIN=12V 2 A

=5V, 7V<VIN<28V,

LDO Output Voltage VCC

Input UVLO Threshold V

IN_UVLO

0<I

<10mA

VCC

Rising Edge 3.5 3.9 4.4 V

Input UVLO Hysteresis 200 mV

4 mA

5.2 5.8 6.4 V

EN High Voltage V

EN Low Voltage V

VEN Rising 1.8 V

EN_HIGH

VEN Falling 0.6 V

EN_LOW

STEP-UP CONVERTER

Gate Driver Impedance (Sourcing) Gate Driver Impedance (Sinking)

Switching Frequency fSW

OSC Voltage V

Maximum Duty Cycle D

OSC

MAX

90 %

=6V,V

=6V,I

= 115k 470 570 670 kHz

OSC

= 374k 140 175 210 kHz

OSC

=6V 4 

GATE

=10mA 2 

GATE

1.17 1.22 1.26 V

ISENSE Limit Max Duty Cycle 150 200 250 mV

COMP Source Current Limit I

COMP SOLI

COMP Sink Current Limit I

COMP Trans-conductance G

65 A

COMP SILI

15 A

COMP

I

=±10uA 400 A/V

COMP

PWM DIMMING

DBRT Leakage Current I

BOSC Frequency f

BOSC Output Current I

-5 5 A

DBRT_LK

BOSC

6 7.5 9 A

BOSC

=2.2nF 1.0 1.5 2 kHz

BOSC

LED CURRENT REGULATION

ISET Voltage V

LEDX Average Current I

Current Matching

(5)

1.17 1.22 1.26 V

ISET

LED

=30k 31 32 33 mA

ISET

=32mA 2.5 %

LED

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MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

ELECTRICAL CHARACTERISTICS (continued)

VIN =12V, VEN = 5V, TA = 25°C, unless otherwise noted.

Parameters Symbol Condition Min Typ Max Units

LEDX Regulation Voltage V

LEDX

LED

=60mA 300 mV

PROTECTION OVP(Over Voltage Protection)

Threshold OVP UVLO threshold V

LEDX UVLO Threshold V

LEDX Over Voltage Threshold V

OVP_OV

OVP_UV

LEDX_UV

LEDX_OV

Rising Edge 1.18 1.23 1.28 V

Step-up Converter Fails 40 75 110 mV

106 196 286 mV

5.6 6.1 6.6 V

Thermal Shutdown Threshold TST 150 °C

Notes:

5) Matching is defined as the difference of the maximum to minimum current divided by 2 times average currents.

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MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

TYPICAL PERFORMANCE CHARACTERISTICS

VIN = 12V, 10LEDs in series 4 strings, 120mA/string, unless otherwise noted.

100

20V/div.

OUT

20V/div.

5A/div.

LED

500mA/div.

Efficiency vs. V

55 50

51015202530

EN Power On

20V/div.

OUT

20V/div.

10V/div.

INDUCTOR

1A/div.

20V/div.

OUT

20V/div.

BOSC

1V/div.

LED

500mA/div.

Steady State

20V/div.

OUT

20V/div.

10V/div.

LED

500mA/div.

20V/div.

OUT

20V/div.

PWMI

5V/div.

LED

500mA/div.

VIN Power On

20V/div.

OUT

20V/div.

LED

500mA/div.

Open LED Protection

Open all LED string at working

20V/div.

500mA/div.

Open LED Protection

Open one LED string at working

OUT

LED

20V/div.

OUT

20V/div.

LED1

20V/div.

LED

500mA/div.

Short LED Protection

Short V

to LEDx at working

OUT

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PIN FUNCTIONS

MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

TSSOP16EP

&SOIC16

Pin #

1 1 COMP

2 2 EN

SOIC20

Pin #

Name Description

Step-up Converter Compensation Pin. This pin compensates the regulation control loop. Connect a ceramic capacitor from COMP to GND.

Enable Control Input. A voltage greater than 1.8V will turn the part on and less than 0.6 V will turn the part off.

Brightness Control Input. Apply a PWM signal on this pin for for external PWM dimming mode. Apply a DC voltage range from 0.2V to 1.2V on this

3 3 DBRT

pin to linearly set the internal dimming duty cycle from 0% to 100% for DCinput PWM dimming mode. The MP3394S has positive dimming polarity on DBRT.

4 5 GND Ground.

Switching Frequency Set. Connect a resistor between OSC and GND to set

5 7 OSC

the step-up converter’s switching frequency. The voltage at this pin is regulated to 1.22V. The clock frequency is proportional to the current sourced from this pin.

LED Current Set. Tie a current-setting resistor from this pin to ground to

6 8 ISET

program the current in each LED string. This pin voltage is regulated to

1.22V. The LED current is proportional to the current through the ISET resistor.

Dimming Repetition Set. This is the timing pin for the oscillator to set the dimming frequency. To use DC input PWM dimming mode, connect a

7 9 BOSC

capacitor from this pin to GND to set the internal dimming frequency. A saw-tooth waveform is generated on this pin. To use external PWM dimming mode, connect a resistor from this pin to GND, and apply the PWM signal on DBRT pin.

8 10 LED4

9 11 LED3

LED String 4 Current Input. This pin is the open-drain output of an internal dimming control switch. Connect the LED String 4 cathode to this pin.

LED String 3 Current Input. This pin is the open-drain output of an internal dimming control switch. Connect the LED String 3 cathode to this pin.

Do not let this pin float.

10 12 LED2

11 13 LED1

LED String 2 Current Input. This pin is the open-drain output of an internal dimming control switch. Connect the LED String 2 cathode to this pin.

LED String 1 Current Input. This pin is the open-drain output of an internal dimming control switch. Connect the LED String 1 cathode to this pin.

Over-Voltage Protection Input. Connect a resistor divider from output to this

12 14 OVP

pin to program the OVP threshold. When this pin voltage reaches 1.23V, the MP3394S triggers Over Voltage Protection mode.

Current Sense Input. During normal operation, this pin senses the voltage across the external-inductor current-sensing resistor (R

13 17 ISENSE

current–mode control and also to limit the inductor current during every

) for peak-

SENSE

switching cycle. If this pin is not used for cascading applications, tie this pin to GND; do not let this pin float.

14 18 GATE

Step-up Converter Power Switch’s Gate Driver Output. This pin drives the external power N-MOS device.

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MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

PIN FUNCTIONS

TSSOP16EP

&SOIC16

Pin #

SOIC20

Pin #

4, 6,

15, 16

(continued)

Name Description

Supply Input. VIN supplies the power to the chip, as well as the step-

VIN

up converter switch. Drive VIN with a 5V to 28V power source. Must be locally bypassed.

The Internal 5.8V Linear Regulator Output. VCC provides power

VCC

supply for the external- MOSFET switch-gate driver and the internal control circuitry. Bypass VCC to GND with a ceramic capacitor.

No Connect.

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MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

FUNCTIONAL BLOCK DIAGRAM

Figure 1—MP3394S Functional Block Diagram

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OPERATION

MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

Employing the peak-current mode and a programmable constant frequency, the MP3394S is a step-up LED driver with 4 channels or regulated current sources to drive an array of up to 4 strings of white LEDs.

Internal Regulator

The MP3394S includes an internal linear regulator (VCC). When VIN is greater than 6V, this regulator outputs a 5.8V power supply to the external MOSFET switch’s gate driver and the internal control circuitry. The VCC voltage drops to 0V when the chip shuts down. The MP3394S features under-voltage lockout (UVLO). The chip is disabled until VCC exceeds the UVLO threshold. The UVLO hysteresis is approximately 200mV.

System Startup

When enabled, the MP3394S checks the topology connection first. The chip monitors the over-voltage protection (OVP) pin to see if the Schottky diode is connected or if the boost output is shorted to GND. An OVP voltage of less than 75mV will disable the chip. The MP3394S also checks other safety limits, including UVLO and over-temperature protection (OTP) after passing the OVP test. If all the protection tests pass, the chip then starts boosting the step-up converter with an internal soft-start.

It is recommended that the enable signal is given after the establishment of the input voltage and PWM dimming signal during the start-up sequence.

the error amplifier (V

), the external MOSFET

COMP

turns off.

The output voltage of the internal error amplifier is an amplified signal of the difference between the reference voltage and the feedback voltage. The converter automatically chooses the lowest active LEDX pin voltage to provide a highenough bus voltage to power all the LED arrays.

If the feedback voltage drops below the reference, the output of the error amplifier increases. This result in more current flowing through the MOSFET, thus increasing the power delivered to the output. This forms a closed loop that regulates the output voltage.

Under light-load operation—where V

 VIN—

OUT

,the converter runs in pulse-skipping mode where the MOSFET turns on for a minimum on-time of approximately 100ns, and then the converter discharges the power to the output for the remaining period. The external MOSFET remains off until the output voltage needs to be boosted again.

Dimming Control

The MP3394S provides two PWM dimming methods: external PWM signal or DC-input PWM dimming mode (see Figure 2).

Ex-PWM Input

DBRT

DPWM

Comparat or

DPWM Output

BOSC

DPWM

Osc illat or

BOSC

Step-Up Converter

The converter’s operating frequency is programmable (from 100kHz to 500kHz) with an external set resistor on the OSC pin. This flexibility helps to optimize the size of external components and improve the efficiency.

Figure 2—PWM Dimming Method

At the beginning of each cycle, the internal clock output a signal to turn on the external MOSFET (minimum turn on time is 100ns). A stabilizing ramp added to the output of the current sense amplifier prevents sub-harmonic oscillations for duty cycles greater than 50 percent. This result is fed into the PWM comparator. When this resulting voltage reaches the output voltage of

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MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

For external PWM dimming, ground the BOSC pin through a resistor, and apply an external PWM signal to the DBRT pin.

For DC-input PWM dimming, apply a DC analog signal to the DBRT pin, and connect a capacitor on BOSC pin to ground. The DC signal is then converted to a DPWM dimming signal with a proportional oscillation frequency.

The brightness of the LED array is proportional to the duty cycle of the DPWM signal. The DPWM signal frequency is set by the capacitor from the BOSC pin to ground.

Open String Protection Open string protection is achieved through the

OVP pin and the LED (1 to 4) pins. If one or more strings are open, the respective LEDX pins are pulled to ground and the IC keeps charging the output voltage until it reaches the over-voltage protection (OVP) threshold. Then the chip marks off the strings which have an LEDX pin voltage lower than 196mV. Once marked, the remaining LED strings force the output voltage back into tight regulation. The string with the largest voltage drop determines the output regulation.

Short String Protection

The MP3394S monitors the LEDX pin voltages to determine if a short string fault has occurred. If one or more strings are shorted, the respective LEDX pins tolerate high voltage stress. If an LEDX pin voltage is higher than 6.1V, this condition triggers the detection of a short string. When a short string faults (LEDX over-voltage fault) keeps for 4096 switching clocks, the fault string is marked OFF and disabled. Once a string is marked OFF, it disconnects from the output voltage loop. The marked LED strings shut off completely until the part restarts. If all strings are shorted, the MP3394S will shut down the step-up converter. The strings remain marked OFF until the chip resets.

Thermal Shut Down Protection

When MP3394S die temperature exceeds the thermal protection threshold, the thermal protection is triggered. IC shuts down until EN restart.

The MP3394S will always attempt to light at least one string. If all strings are open, the MP3394S shuts down the step-up converter. The strings will remain in this marked state until the chip reset.

Page 11

MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

)

APPLICATION INFORMATION

Selecting the Switching Frequency

The switching frequency of the step-up converter is recommended from 100kHz to 500kHz for most of application. An oscillator resistor on OSC pin sets the internal oscillator frequency for the step-up converter according to the equation:

f(kHz)

For R

=374k, the switching frequency is set

OSC

to 185 kHz.

Setting the LED Current

The LED string currents are identical and set through the current setting resistor on the ISET pin. The ISET pin can not be open.

LED

I(mA)

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 4.7F ceramic capacitor in parallel with a 220µF electrolytic capacitor.

Selecting the Inductor and Current Sensing Resistor

The MP3394S requires an inductor to supply a higher output voltage while being driven by the input voltage. A larger value inductor results in less ripple current, resulting in lower peak inductor current and reducing stress on the internal N-channel MOSFET. However, the larger value inductor has a larger physical size, higher series resistance, and lower saturation current.

Choose an inductor that does not saturate under the worst-case load conditions. Select the 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 the equation:

69190

R(k)

OSC

800 1.22V

SET

(R 0.5)k

+Ω

LOAD

Where V voltages, f

 V D(1D

×××−

≥

and V

is the switching frequency, I

OUT

2 f I

××

SW LOAD

1D −=

OUT

are the input and output

OUT

the LED load current, and  is the efficiency. The switching current is usually used for the peak

current mode control. In order to avoid hitting the current limit, the voltage across the sensing resistor R the worst-case current-limit voltage, V

L(PEAK)

Where I

L(PEAK)

current. V

Figure 3—V

must measure less than 80% of

SENSE

0.8 V

SENSE

VI V(V-V)

OUT LOAD IN OUT IN

V 2LfV

L(PEAK)

××

IN SW OUT

×× ×

is the peak value of the inductor

is shown in Figure 3.

SENSE

Vsense vs. Duty Cycle

500

400

300

200

100

CURRENT LIMIT-VSENSE (mV)

0 1020 3040 506070 8090100

DUTY CYCLE (%)

vs Duty Cycle

SENSE

Selecting the Power MOSFET

The MP3394S is capable of driving a wide variety of N-channel power MOSFETS. The critical parameters of selection of a MOSFET are:

1. Maximum drain-to-source voltage, V

2. Maximum current, I On-resistance, R

DS(ON)

D(MAX)

DS(MAX)

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MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

−

4. Gate source charge QGS and gate drain charge Q

5. Total gate charge, Q

Ideally, the off-state voltage across the MOSFET is equal to the output voltage. Considering the voltage spike when it turns off, V

DS(MAX)

should be

greater than 1.5 times of the output voltage.

The maximum current through the power MOSFET occurs at the maximum input voltage and the maximum output power. The maximum RMS current through the MOSFET is given by

IID=×

RMS(MAX) IN(MAX) MAX

OUT IN(MIN)

≈

MAX

, where:

OUT

The current rating of the MOSFET should be greater than 1.5xI

RMS

The ON resistance of the MOSFET determines the conduction loss, which is given by:

RMScond

(on) DS

kRIP

××=

Where k is the temperature coefficient of the MOSFET.

The switching loss is related to Q

and Q

which determine the commutation time. Q

GS1

is the charge between the threshold voltage and the plateau voltage when a driver charges the gate, which can be read in the chart of V of the MOSFET datasheet. Q

is the charge

vs. QG

during the plateau voltage. These two parameters are needed to estimate the turn-on and turn-off losses.

SW DS IN SW

Where V

is the threshold voltage, V

plateau voltage, R

is the drain-source voltage. Please note that

−

DR TH

GD G

DR PLT

×××

VIf

−

DS IN SW

is the gate resistance, and

PLT

is the

GS1 G

=×××+

PVIf

calculating the switching loss is the most difficult part in the loss estimation. The formula above provides a simplified equation. For more accurate estimates, the equation becomes much more complex.

The total gate charge, Q

, is used to calculate

the gate drive loss. The expression is

fVQP ××

SWDRGDR

Where V

is the drive voltage.

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. For most applications, a

4.7F ceramic capacitor in parallel with a 22F electrolytic capacitor will suffice.

Setting the Over Voltage Protection

The open string protection is achieved through the detection of the voltage on the OVP pin. In some cases, an LED string failure results in the feedback voltage always zero. The part then keeps boosting the output voltage higher and higher. If the output voltage reaches the programmed OVP threshold, the protection will be triggered.

To ensure the chip functions properly, select the resistor values for the OVP resistor divider to provide an appropriate set voltage. The recommended OVP point is about 1.1 to 1.2 times higher than the output voltage for normal operation.

V1.23(1 )

=×+

OVP

HIGH

LOW

Selecting Dimming Control Mode

The MP3394S provides two different dimming methods

1. Direct PWM Dimming

An external PWM dimming signal is employed to achieve PWM dimming control. Connect a 100k resistor from BOSC pin to GND and apply a PWM dimming signal—in the range of 100Hz to 20kHz—to the DBRT pin. The minimum recommended amplitude of the PWM signal is

1.2V. The low level should be less than 0.4V (See Figure 4).

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MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

Figure 4—Direct PWM Dimming

Table 1 shows the PWM dimming duty Range with different PWM dimming frequency for most of applications.

Table 1 The Range of PWM Dimming Duty

(Hz) D

PWM

100<f≤200 200<f≤500

500<f≤1k

1k<f≤2k 2k<f≤5k

5k<f≤10k

10k<f≤20k

min

0.30% 100%

0.75% 100%

1.50% 100%

3.00% 100%

7.50% 100%

15.00% 100%

30.00% 100%

max

2. DC Input PWM Dimming

For DC input PWM dimming, apply an analog signal (ranging from 0.2 V to 1.2V) to the DBRT pin to modulate the LED current directly. If the DBRT voltage falls below 0.2V, the PWM duty cycle will be 0%. If the DBRT voltage goes above

1.2V, the output will be 100% (See Figure 5). The capacitor on BOSC pin sets the frequency of the internal triangle waveform according to the equation.

Expanding LED Channels

The MP3394S can expand the number of LED channels by using two or three MP3394Ss in parallel. To connect two MP3394Ss for a total of 8 LED strings, tie the VCC pins of the master IC and the slave IC together to power the slave IC’s internal logic circuitry. Tie the COMP pins of the slave IC and the master IC together to regulate the voltage of all 8 strings LEDs. The slave IC MOSFET driving signals are not used; the boost converter can be only driven by the master IC. Do not leave the I

pin of the slave IC floating;

SENSE

tie it to ground. Apply the EN and DIM signals to both ICs. For best results, use external PWM dimming mode for synchronized and accurate dimming.

Layout Considerations

The circuit layout for the MP3394S requires special attention to reduce EMI noise.

The loop from the external MOSFET (M1), through the output diode (D1) and the output capacitor (C2, C3) carry a high-frequency pulse current and must be as small and short as possible (See Figure 6).

(kHz)= 3.5 / C

BOSC

Chose a dimming frequency in the range of 100Hz to 20kHz.

BOSC

(nF)

Figure 6—Layout Consideration

All logic signals refer to the signal ground. In order to reduce the noise affection, it is recommend to separate the power ground(PGND) and signal ground(GND), then connect PGND and GND together through single joint.

External MOSFET for Short Protection

When output voltage is higher than rating of LED1-4 pins, external MOSFET is needed for

Figure 5—DC input PWM Dimming

each LED channel to avoid destroying LED1-4 pins. (See Figure 8)The rating of MOSFET must be higher than 1.2* V

t and more than 1.2* I

OUT

LED

Page 14

MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

TYPICAL APPLICATION CIRCUITS

8V-28V

VIN

GND

DIM

R16

C11

C13

R11

20k

R14

100k

C10

R18

20k

470nF

C12

R10

330k

270

R17

7.68k

VIN

VCC

COMP

MP3394S

OSC

BOSC

DBRT

ISET

GATE

ISENSE

GND

OVP

LED1

LED2

LED3

LED4

100V/4A

R19

C14

0.05

R12

R13

R15

B360

357k

10k

12S 4P 120mA/string

LED

LED1 LED2 LED3 LED4

8V-28V

VIN

GND

DIM

Figure 1—Application Circuit

C4NCC5

18S 4P 120mA/string

B360

R16

0.05

R12

R13

R15

100V/4A

GND

C10

470nF

C13

GND

R11

20k

R14

100k

GND

R18

20k

GND

C11

R10

220k

C12

GND

270

R17

7.68k

VIN

VCC

COMP

OSC

BOSC

DBRT

ISET

MP3394S

GATE

ISENSE

GND

OVP

LED1

LED2

LED3

LED4

562k

10k

GND

,6 5

1,2,

M2-M5: AM3490N 100V/1A TSOP-6

5,6 2,

VIN

1,2,5,6

R19

R20

Figure 8 – Drive 18LEDs in Series, 4 strings 120mA/string

Note: For Vin>15V application, use R19 and R20(10kΩ) divider to make a 15V bias voltage for M2-M5.

LED

LED1 LED2

LED3 LED4

1,2,5,6

Page 15

PACKAGE INFORMATION

TSSOP16（with external thermal pad）

MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

PIN 1 ID

0.80

1.05

4.90

5.10

916

4.30

4.50

6.20

6.60

TOP VIEW

1.20 MAX SEATING PLANE

0.19

0.30

0.65 BSC

0.00

0.15

FRONT VIEW

4.20 TYP

0.40 TYP

1.60 TYP

0.65 BSC

RECOMMENDED LAND PATTERN

SEE DETAIL "A"

SIDE VIEW

3.30 TYP

5.80 TYP

0.09

0.20

GAUGE PLANE

0.25 BSC

3.65

4.15

0o-8

0. 45

0. 75

DETAIL “A”

2.80

3.30

BOTTOM VIEW

NOTE:

1) ALL DIMENSIONS ARE IN MILLIMETERS.

2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH, PROTRUSION OR GATE BURR.

3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION.

4) LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.10 MILLIMETERS MAX.

5) DRAWING CONFORMS TO JEDEC MO-153, VARIATION ABT.

6) DRAWING IS NOT TO SCALE.

Page 16

0.386( 9.80)

0.394(10.00)

MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

SOIC16

0.050(1.27)0.024(0.61)

0.063 (1.60)

PIN 1 ID

0.013(0.33)

0.020(0.51)

GAUGE PLANE

0.010(0.25) BSC

0o-8

TOP VIEW

FRONT VIEW

0.010(0.25)

0.020(0.50)

0.016(0.41)

0.050(1.27)

DETAIL "A"

0.050(1.27) BSC

x 45

0.150

(3.80)

0.157

(4.00)

0.004(0.10)

0.010(0.25)

0.228

(5.80)

0.244

(6.20)

RECOMMENDED LAND PATTERN

0.053(1.35)

0.069(1.75) SEATING PLANE

SEE DETAIL "A"

SIDE VIEW

NOTE:

1) CONTROL DIMENSION IS IN INCHES. DIMENSION IN BRACKET IS IN MILLIMETERS.

2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.

3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.

4) LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.004" INCHES MAX.

5) DRAWING CONFORMS TO JEDEC MS-012, VARIATION AC.

6) DRAWING IS NOT TO SCALE.

0.213 (5.40)

0.0075(0.19)

0.0098(0.25)

Page 17

MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

SOIC20

PIN 1 ID

0.013(0.33)

0.020(0.51)

0.024 (0.61)

0.079 (2.00)

RECOMMENDED LAND PATTERN

SEE DETAIL "A"

0.496(12.60)

0.512(13.00) 11

0.291 (7.40)

0.299 (7.60)

0.394

(10.00)

0.418

(10.60)

TOP VIEW

0.093(2.35)

0.104(2.65) SEATING PLANE

0.050(1.27) BSC

0.004(0.10)

0.012(0.30)

FRONT VIEW SIDE VIEW

0.050 (1.27)

0.370 (9.40)

0.009(0.23)

0.013(0.33)

GAUGE PLANE

0.010(0.25) BSC

0o-8

0.010(0.25)

0.030(0.75)

0.016(0.41)

0.050(1.27)

DETAIL "A"

x 45

NOTE:

1) CONTROL DIMENSION IS IN INCHES. DIMENSION IN BRACKET IS IN MILLIMETERS.

2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.

3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.

4) LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.10 MILLIMETERS MAX.

5) DRAWING CONFORMS TO JEDEC MS-013, VARIATION AC.

6) DRAWING IS NOT TO SCALE.

NOTICE: The information in this document is subject to change without notice. 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.

Datasheet MP3394SGS Specification

Specifications and Main Features

Frequently Asked Questions

User Manual