MIC3223YTSE Micrel Inc, MIC3223YTSE Datasheet

Page 1

... Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. _______________________________________________________________________________________________________________________ Typical Application Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com January 2010 MIC3223 High Power Boost LED Driver with ...

Page 2

... Micrel, Inc. Ordering Information Part Number MIC3223YTSE Pin Configuration Pin Description Pin Number Pin Name COMP OVP 6 PGND 7,8,9, VIN 12 DRVVDD 13 VDD 14 DIM_IN 15 DIM_OUT 16 AGND 17 EP January 2010 Junction Temp. Range –40° to +125°C 16-Pin ePad TSSOP (TSE) Pin Function Enable (Input): Logic high enables and logic low disables operation ...

Page 3

Micrel, Inc. Absolute Maximum Ratings Supply Voltage (V ) .....................................................+22V IN Switch Voltage (V )..................................... -0.3V to +42V SW Regulated Voltage (V ) ............................... -0.3V to +6.5V DD Dimming In Voltage (V ) ...............-0. DIM_IN Dimming Out Voltage ...

Page 4

Micrel, Inc. Symbol Parameter DIM MIN Minimum Dimming Pulse R DIM_OUT Resistance High DO R DIM_OUT Resistance Low DO F Oscillator Frequency SW R Soft Start Resistance SS Over Temperature Threshold T SD Shutdown Notes 1. Exceeding the absolute maximum ...

Page 5

Micrel, Inc. Typical Characteristics Efficiency v s. Input Voltage 25° 25V OUT 0.5A OUT INPUT VOLT AGE (V) Feedback Voltage v ...

Page 6

Micrel, Inc. Typical Characteristics (continued) Efficiency v s. Output Current 10V 25V OUT 80 0 0.5 1 OUT PUT CURRENT (A) January 2010 Efficiency v s. Output Current 96 94 ...

Page 7

Micrel, Inc. Functional Characteristics January 2010 7 MIC3223 M9999-011510-A ...

Page 8

Micrel, Inc. Functional Characteristics (continued) January 2010 8 MIC3223 M9999-011510-A ...

Page 9

Micrel, Inc. Functional Diagram January 2010 9 MIC3223 M9999-011510-A ...

Page 10

Micrel, Inc. Functional Description A constant current output converter is the preferred method for driving LEDs. Small variations in current have a minimal effect on the light output, whereas small variations in voltage have a significant impact on light output. ...

Page 11

Micrel, Inc. Application Information Constant Output Current Converter The MIC3223 is a peak current mode boost converter designed to drive high power LEDs with a constant current output. The MIC3223 operates with an input voltage range from 4.5V to 20V. ...

Page 12

Micrel, Inc. Figure 1. Soft start LED Dimming The MIC3223 LED driver can control the brightness of the LED string via the use of pulse width modulated (PWM) dimming. An input signal from 20kHz can be applied ...

Page 13

Micrel, Inc. Figure 5. PWM Dimming 20% and I In Figure 100Hz dimming frequency and Figure 5 is 1kHz dimming frequency. The time it takes for the LED current to reach it full value is longer with ...

Page 14

Micrel, Inc. Design Procedure for a LED Driver Symbol Input V Input Voltage IN I Input Current IN Output LEDs Number of LEDs V Forward Voltage of LED F V Output Voltage OUT I LED Current LED I Required I ...

Page 15

Micrel, Inc. Design Example In this example, we will be designing a boost LED driver operating off a 12V input. This design has been created to drive 6 LEDs at 350mA with a ripple of about 20%. We are designing ...

Page 16

Micrel, Inc. Eq. ( INDUCTOR IN_RMS(max) A Coilcraft # MSS1260-223ML is used in this example. Its DCR is 52mΩ, I =2.7A SAT 1.54 × 52 mΩ = 0.123W INDUCTOR Output Capacitor In this LED ...

Page 17

Micrel, Inc. L parisitic Eq.(17 snubber The explanation of the method to find the best R snubber is beyond the scope of this data sheet. Use R = 2Ω, ½ watt and C snubber snubber The power dissipation ...

Page 18

Micrel, Inc. This greatly simplifies the compensation. One needs only to get a bode plot of the transfer function of the control to output G (s) with a network analyzer vc and/or calculate it. From the bode plot find what ...

Page 19

Micrel, Inc. Other Applications Figure 13. MIC3223 Typical Application without External PWM Dimming Switch Audio noise Audio noise from the output capacitors may exits in a standard boost LED converter. The physical dimensions of ceramic capacitors change with the voltage ...

Page 20

Micrel, Inc. Evaluation Board Schematic January 2010 37V Max 1A LED Driver 20 MIC3223 M9999-011510-A ...

Page 21

Micrel, Inc. Bill of Materials Item Part Number GRM319R61E475KA12D C1 C3216X7R1E475M 12063D475KAT2A C2 GRM188R71C273KA01D GRM188R60J106ME47D C3, C7 C1608X5R0J106K 08056D106MAT2A 12105C475KAZ2A C4, C6 GRM32ER71H475KA88L GRM188R71C473KA01D C5 0603YC473K4T2A C8 GRM188R72A102KA37D D1 SK35B L1 MSD1260-223ML-LD R1, R3 CRCW0603100KFKEA R2 CRCW0603549RFKEA R4 CRCW06033K24FKEA R5 ...

Page 22

Micrel, Inc. PCB Layout Recommendations January 2010 Top Layer Bottom Layer 22 MIC3223 M9999-011510-A ...

Page 23

Micrel, Inc. Package Information January 2010 16-Pin ePad TSSOP (TSE) 23 MIC3223 M9999-011510-A ...

Page 24

Micrel, Inc. Recommended Land Pattern MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and ...