Datasheet

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OVP

nDIM

LM3421

AGND

PGND

DDRV

DAP

GATE

COMP

CSH

RCT

HSP

RPD

HSN

LED

PWM

LM3421, LM3421-Q1

LM3423, LM3423-Q1

www.ti.com

SNVS574E –JULY 2008–REVISED MAY 2013

N-Channel Controllers for Constant Current LED Drivers

Check for Samples: LM3421, LM3421-Q1, LM3423, LM3423-Q1

FEATURES

DESCRIPTION

The LM3421/23 are versatile high voltage N-channel

• LM3421Q1/LM3423Q1 are Automotive Grade

MosFET controllers for LED drivers . They can be

Products That are AEC-Q100 Grade 1 Qualified

easily configured in buck, boost, buck-boost and

(-40°C to +125°C Operating Junction

SEPIC topologies. This flexibility, along with an input

Temperature) and Similarly

voltage rating of 75V, makes the LM3421/23 ideal for

LM3421Q0/LM3423Q0 are AEC-Q100 Grade 0

illuminating LEDs in a large family of applications.

Qualified (-40°C to +150°C Operating Junction

Adjustable high-side current sense voltage allows for

Temperature)

tight regulation of the LED current with the highest

• V

Range From 4.5V to 75V

efficiency possible. The LM3421/23 uses Predictive

• High-Side Adjustable Current Sense

Off-time (PRO) control, which is a combination of

peak current-mode control and a predictive off-timer.

• 2Ω, 1A Peak MosFET Gate Driver

This method of control eases the design of loop

• Input Under-Voltage and Output Over-Voltage

compensation while providing inherent input voltage

Protection

feed-forward compensation.

• PWM and Analog Dimming

The LM3421/23 devices include a high-voltage

• Cycle-by-Cycle Current Limit

startup regulator that operates over a wide input

• Programmable Switching Frequency

range of 4.5V to 75V. The internal PWM controller is

designed for adjustable switching frequencies of up to

• "Zero Current" Shutdown and Thermal

2.0 MHz, thus enabling compact solutions. Additional

Shutdown

features include "zero current" shutdown, analog

• LED Output Status Flag (LM3423/23Q1/23Q0

dimming, PWM dimming, over-voltage protection,

Only)

under-voltage lock-out, cycle-by-cycle current limit,

and thermal shutdown.

• Fault Status Flag and Timer

(LM3423/23Q1/23Q0 Only)

The LM3423 also includes an LED output status flag,

a fault flag, a programmable fault timer, and a logic

APPLICATIONS

input to select the polarity of the dimming output

driver.

• LED Drivers - Buck, Boost, Buck-Boost, and

SEPIC

The LM3421Q1/23Q1 are AEC-Q100 grade 1

qualified and LM3421Q0/23Q0 are AEC-Q100 grade

• Indoor and Outdoor Area SSL

0 qualified.

• Automotive

• General Illumination

• Constant-Current Regulators

Typical Boost Application Circuit

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (67 pages)

PAGE 1
LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 N-Channel Controllers for Constant Current LED Drivers Check for Samples: LM3421, LM3421-Q1, LM3423, LM3423-Q1 FEATURES DESCRIPTION • The LM3421/23 are versatile high voltage N-channel MosFET controllers for LED drivers . They can be easily configured in buck, boost, buck-boost and SEPIC topologies.
PAGE 2
LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com EFFICIENCY (%) 100 95 90 85 80 10 15 20 25 30 VIN (V) Figure 1.
PAGE 3
LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 PIN DESCRIPTIONS (continued) LM3423 LM3421 Name Description Function Connect a PWM signal for dimming as detailed in the PWM DIMMING section and/or a resistor divider from VIN to program input under-voltage lockout (UVLO). Turn-on threshold is 1.24V and hysteresis for turn-off is provided by 23 µA current source.
PAGE 4
LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Absolute Maximum Ratings (1) (2) VIN, EN, RPD, nDIM -0.3V to 76.0V -1 mA continuous OVP, HSP, HSN, LRDY, FLT, DPOL -0.3V to 76.0V -100 µA continuous RCT -0.3V to 76.0V -1 mA to +5 mA continuous IS -0.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 Electrical Characteristics (1) Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating Temperature Range ( TJ = −40°C to +150°C for LM3421Q0/LM3423Q0, TJ = −40°C to +125°C for all others). Specifications that differ between the two operating ranges will be identified in the Temp Range column as Q0 for TJ = −40°C to +150°C and as Q1 for TJ = −40°C to +125°C.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com Electrical Characteristics (1) (continued) Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating Temperature Range ( TJ = −40°C to +150°C for LM3421Q0/LM3423Q0, TJ = −40°C to +125°C for all others).
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 Electrical Characteristics (1) (continued) Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating Temperature Range ( TJ = −40°C to +150°C for LM3421Q0/LM3423Q0, TJ = −40°C to +125°C for all others).
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics TA=+25°C and VIN = 14V unless otherwise specified Boost Efficiency vs. Input Voltage VO = 32V (9 LEDs) (1) Buck-Boost Efficiency vs. Input Voltage VO = 21V (6 LEDs) (2) 100 95 95 EFFICIENCY (%) EFFICIENCY (%) 100 90 85 90 85 80 75 70 80 15 20 25 30 0 16 32 48 64 80 VIN (V) VIN (V) Figure 4. Figure 5. Boost LED Current vs.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 Typical Performance Characteristics (continued) TA=+25°C and VIN = 14V unless otherwise specified VCSH vs. Junction Temperature VCC vs. Junction Temperature 7.20 1.250 7.10 1.240 7.00 VCC (V) VCSH (V) 1.245 1.235 1.230 6.90 1.225 6.80 1.220 6.70 -50 -14 22 58 94 130 -50 -14 22 58 94 130 TEMPERATURE (°C) TEMPERATURE (°C) Figure 10. Figure 11. VRCT vs. Junction Temperature VLIM vs.
PAGE 10
LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com BLOCK DIAGRAM VIN 6.9V LDO Regulator EN VCC 820k UVLO (4.1V) VCC UVLO REFERENCE 500k VIN UVLO Standby HYSTERESIS 23 PA nDIM 1.235V VCC TLIM Thermal DPOL Limit Dimming 1.24V DDRV OVLO LatchOff RCT PGND Reset Dominant Start new on time VIN/25 LEB VCC Q S GATE R W = 150 ns PGND COMP RPD 23 PA PWM 1.235V OVP HYSTERESIS EN CSH OVP OVLO 800 mV LOGIC STOP HSP HSN 1.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 function with external dimming FET driver allows for fast PWM dimming of the LED load. When designing, the maximum attainable LED current is not internally limited because the LM3421/23 is a controller. Instead it is a function of the system operating point, component choices, and switching frequency allowing the LM3421/23 to easily provide constant currents up to 5A.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com PREDICTIVE OFF-TIME (PRO) CONTROL PRO control is used by the LM3421/23 to control ILED. It is a combination of average peak current control and a one-shot off-timer that varies with input voltage. The LM3421/23 uses peak current control to regulate the average LED current through an array of HBLEDs.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 VIN VSW LM3421/23 RSNS VIN/25 RT Start tON RCT RT LM3421/23 CT VIN/25 Reset timer LED- Start tON RCT CT Reset timer Figure 16. Off-timer Circuitry for Boost and Buckboost Regulators Figure 17. Off-timer Circuitry for Buck Regulators LM3421/23 ILED VSNS RHSP RSNS RHSN RCSH HSP High-Side Sense Amplifier HSN CSH ICSH Error Amplifier To PWM Comparator 1.24V CCMP COMP Figure 18.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com The selection of the three resistors (RSNS, RCSH, and RHSP) is not arbitrary. For matching and noise performance, the suggested signal current ICSH is approximately 100 µA. This current does not flow in the LEDs and will not affect either the off-state LED current or the regulated LED current. ICSH can be above or below this value, but the high-side amplifier offset characteristics may be affected slightly.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 Method 2 provides a complete dimming range and better noise performance, though it is more complex. It consists of a PNP current mirror and a bias network consisting of an NPN, 2 resistors and a potentiometer (RADJ), where RADJ controls the amount of current sourced into the CSH pin.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com OVER-CURRENT PROTECTION The LM3421/23 devices have a secondary method of over-current protection. Switching action is disabled whenever the current in the LEDs is more than 30% above the regulation set point. The dimming MosFET switch driver (DDRV) is not disabled however as this would immediately remove the fault condition and cause oscillatory behavior.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 And the right half plane zero (ωZ1) is: rD x Dc2 ZZ1 = D x L1 (18) 100 öZ1 80 135 öP1 90 GAIN GAIN (dB) 0 40 PHASE -45 20 0° Phase Margin -90 0 -20 -135 -40 -180 -60 1e-1 PHASE (°) 45 60 1e1 1e3 1e5 -225 1e7 FREQUENCY (Hz) Figure 22. Uncompensated Loop Gain Frequency Response Figure 22 shows the uncompensated loop gain in a worst-case scenario when the RHP zero is below the output pole.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 ZP2 = www.ti.com 1 5e6: x CCMP (19) It may also be necessary to add one final pole at least one decade above the crossover frequency to attenuate switching noise and, in some cases, provide better gain margin. This pole can be placed across RSNS to filter the ESL of the sense resistor at the same time. Figure 23 shows how the compensation is physically implemented in the system.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 START-UP REGULATOR The LM3421/23 includes a high voltage, low dropout bias regulator. When power is applied, the regulator is enabled and sources current into an external capacitor (CBYP) connected to the VCC pin. The recommended bypass capacitance for the VCC regulator is 2.2 µF to 3.3 µF.
PAGE 20
LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com Floating §0.5 x R OV1+ R OV2· ¸ VTURN - OFF = 1.24V x ¨¨ ¸ R OV1 ¹ © (27) In the ground referenced configuration, the voltage across ROV2 is VO - 1.24V whereas in the floating configuration it is VO - 620 mV where 620 mV approximates VBE of the PNP. The over-voltage hysteresis (VHYSO) is defined: VHYSO = 23 PA x ROV2 (28) LED+ ROV2 LM3421/23 LEDOVP ROV1 Figure 27.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com VTURN SNVS574E – JULY 2008 – REVISED MAY 2013 ON - §R + RUV2· ¸ = 1.24V x ¨¨ UV1 ¸ © RUV1 ¹ (29) The hysteresis (VHYS) is defined as follows: UVLO only VHYS = 23 PA x RUV2 (30) PWM dimming and UVLO § R x (RUV1 + RUV2)· ¸ VHYS = 23 PA x ¨¨RUV2 + UVH ¸ RUV1 ¹ © (31) When "zero current" shutdown and UVLO are implemented together, the EN pin can be used to escape UVLO.
PAGE 22
LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com The series dimFET will open the LED load, when nDIM is low, effectively speeding up the rise and fall times of the LED current. Without any dimFET, the rise and fall times are limited by the inductor slew rate and dimming frequencies above 1 kHz are impractical. Using the series dimFET, dimming frequencies up to 30 kHz are achievable.
PAGE 23
LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 LM3421/23 RSNS 100 k: 10V Q2 100 nF DDRV Figure 31. Buck Level-Shifted PWM Circuit VO LM3421/23 RSNS DPOL 100 k: 10V Q2 VCC Q6 100 pF 10 k: DDRV Figure 32. Boost Level-Shifted PWM Circuit LM3423 ONLY: DPOL, FLT, TIMR, and LRDY The LM3423 has four additional pins: DPOL, FLT, TIMR, and LRDY. The DPOL pin is simply used to invert the DDRV polarity .
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com 1. The EN pin is pulled low long enough for the VCC pin to drop below 4.1V (approximately 200 ms). 2. The TIMR pin is pulled to ground. 3. A complete power cycle occurs. When using the EN and OVP pins in conjunction with the RPD pull-down pin, a race condition exists when exiting the disabled (EN low) state.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 In general, ΔiLED-PP is recommended by manufacturers to be less than 40% of the average LED current (ILED). Therefore, for the buck regulator with no output capacitance, ΔiL-PP should also be less than 40% of ILED. For the boost and buck-boost topologies, ΔiL-PP can be much higher depending on the output capacitance value.
PAGE 26
LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com The chosen input capacitors must also have the necessary RMS current rating. Ceramic capacitors are again the best choice due to their high ripple current rating, long lifetime, and good temperature performance. An X7R dieletric rating is suggested. For most applications, it is recommended to bypass the VIN pin with an 0.1 µF ceramic capacitor placed as close as possible to the pin.
PAGE 27
LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 Boost Inrush Diode L1 D1 VIN VO Q1 Figure 35. Boost Topology with Inrush Diode CIRCUIT LAYOUT The performance of any switching regulator depends as much upon the layout of the PCB as the component selection. Following a few simple guidelines will maximimize noise rejection and minimize the generation of EMI within the circuit.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 Design Guide Refer to the Basic Topology Schematics section.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com Buck (Constant Ripple vs. VIN) RT = 25 x ( VIN - VO ) fSW x CT X VIN (39) 2 RT = 25 x (VIN x VO - VO fSW x C T x ) 2 VIN (40) Boost and Buck-boost RT = 25 fSW x C T (41) 3.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 Boost and Buck-boost 1 §'IL-PP x D' · x x 1+ IL-RMS = ¸ 12 ¨ ILED D' ILED © 2 ¹ (47) 5. LED RIPPLE CURRENT Set the nominal LED ripple current (ΔiLED-PP), by solving for the output capacitance (CO): Buck CO = 'iL - PP 8 x fSW x rD x 'iLED - PP (48) Boost and Buck-boost ILED x D ü CO = rD x LED - PP x fSW i (49) To set the worst case LED ripple current, use DMAX when solving for CO.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 300 CCMP = 1 ZP2 x 5e6 (64) If analog dimming is used, CCMP should be approximately 4x larger to maintain stability as the LEDs are dimmed to zero. A high frequency compensation pole (ωP3) can be used to attenuate switching noise and provide better gain margin.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com Boost ICIN-RMS = 'iL-PP 12 (73) Buck-boost ICIN-RMS = ILED x DMAX 1-DMAX (74) 9.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 Boost VRD-MAX = VO (84) Buck-boost VRD-MAX = VIN-MAX + VO (85) The current rating should be at least 10% higher than the maximum average diode current (ID-MAX): Buck ID-MAX = (1 - DMIN) x ILED (86) Boost and Buck-boost ID-MAX = ILED (87) Replace DMAX with D in the ID-MAX equation to solve for the average diode current (ID).
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com Method #2: If PWM dimming is required, a three resistor network is suggested. To set VTURN-ON, assume RUV2 = 10 kΩ and solve for RUV1 as in Method #1. To set VHYS, solve for RUVH: RUVH = R UV1 x (VHYS - 23 PA x RUV2) 23 PA x (RUV1 + R UV2) (94) 13. PWM DIMMING METHOD PWM dimming can be performed several ways: Method #1: Connect the dimming MosFET (Q3) with the drain to the nDIM pin and the source to AGND.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 Design Example DESIGN #1 - LM3421 BUCK-BOOST Application 10V ± 70V VIN L1 D1 1 CIN RT CCMP RCSH 2 3 4 5 VIN LM3421 HSN EN HSP COMP RPD CSH IS RCT VCC 16 RHSN 15 RHSP 1A ILED CO 14 13 CFS RSNS VIN 12 RFS CBYP CT 6 AGND GATE OVP PGND 11 Q1 RUV2 7 10 ROV2 RLIM DAP 8 nDIM DDRV 9 VIN RUV1 COV Q2 ROV1 SPECIFICATIONS N=6 VLED = 3.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com VTURN-ON = 10V VHYS = 3V VTURN-OFF = 40V VHYSO = 10V 1. OPERATING POINT Solve for VO and rD: VO = N x VLED = 6 x 3.5V = 21V (95) rD = N x rLED = 6 x 325 m: = 1. 95: (96) Solve for D, D', DMAX, and DMIN: D= VO 21V = = 0.467 VO + VIN 21V + 24V (97) D' = 1 - D = 1 - 0. 467 = 0. 533 DMIN = DMAX = 40 (98) VO 21V = = 0.231 VO + VIN-MAX 21V + 70V (99) VO 21V = = 0.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 2. SWITCHING FREQUENCY Assume CT = 1 nF and solve for RT: RT = 25 25 = = 50 k: fSW x CT 500 kHz x 1 nF (101) The closest standard resistor is 49.9 kΩ therefore fSW is: fSW = 25 25 = = 501 kHz RT x CT 49.9 k: x 1 nF (102) The chosen component from step 2 is: CT = 1 nF RT = 49.9 k: (103) 3. AVERAGE LED CURRENT Solve for RSNS: V 100 mV RSNS = SNS = = 0.1: ILED 1A (104) Assume RCSH = 12.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com L1 = 33 PH (111) 5. OUTPUT CAPACITANCE Solve for CO: ILED x D rD x 'iLED- PP x fSW CO = CO = 1A x 0. 467 = 39.8 PF 1.95: x 12 mA x 5 01 kHz (112) The closest capacitance totals 40 µF therefore ΔiLED-PP is: 'iLED- PP = ILED x D rD x CO x fSW 'iLED- PP = 1A x 0. 467 = 12 mA 1.95 : x 40 PF x 5 01 kHz (113) Determine minimum allowable RMS current rating: ICO- RMS = ILED x DMAX 0.677 = 1.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com TU0 = SNVS574E – JULY 2008 – REVISED MAY 2013 Dc x 620V (1+ D) x ILED x R LIM = 0.533 x 620V = 5630 1.467 x 1A x 0.04: (121) To ensure stability, calculate ωP2: ZP2 = min(ZP1, ZZ1) 5 x TU0 rad sec rad = 0. 675 = = sec 5 x 5630 5 x 5630 19k ZP1 (122) Solve for CCMP: CCMP = 1 1 = = 0.30 PF 6 rad ZP2 x 5 e : 0.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 IT- MAX = www.ti.com 0. 677 x 1A = 2.1A 1- 0.677 (131) A 100V NFET is chosen with a current rating of 32A due to the low RDS-ON = 50 mΩ. Determine IT-RMS and PT: IT - RMS = ILED 1A x D= x 0.467 = 1. 28A 0. 533 Dc (132) 2 PT = IT- RMS x RDSON = 1. 28A2 x 50 m: = 82 mW (133) The chosen component from step 9 is: Q1 o 32A, 100V, DPAK (134) 10.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 12. OUTPUT OVLO Solve for ROV2: ROV2 = VHYSO 10V = = 435 k: 23 P A 23 P A (144) The closest standard resistor is 432 kΩ therefore VHYSO is: VHYSO = ROV2 x 23 PA = 432 k: x 23 PA = 9.94V (145) Solve for ROV1: R OV1 = 1.24V x ROV2 1.24V x 432 k: = = 13.6 k: VTURN - OFF - 0.62V 40V - 0.62V (146) The closest standard resistor is 13.7 kΩ making VTURN-OFF: VTURN - OFF = 1.24V x (0.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com APPLICATIONS INFORMATION The following designs are provided as reference circuits. For a specific design, the steps in the Design Procedure section should be performed. In all designs, an RC filter (0.1 µF, 10Ω) is recommended at VIN placed as close as possible to the LM3421/23 device. This filter is not shown in the following designs.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 DESIGN #2 Bill of Materials Qty Part ID Part Value Manufacturer Part Number 1 LM3421 Boost controller TI LM3421MH 1 CBYP 2.2 µF X7R 10% 16V MURATA GRM21BR71C225KA12L 1 CCMP 0.1 µF X7R 10% 25V MURATA GRM21BR71E104KA01L 0 CFS DNP 4 CIN 4.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 DESIGN #3 Bill of Materials Qty Part ID Part Value Manufacturer Part Number 1 LM3421 Buck-boost controller TI LM3421MH 1 CB 100 pF COG/NPO 5% 50V MURATA GRM2165C1H101JA01D 1 CBYP 2.2 µF X7R 10% 16V MURATA GRM21BR71C225KA12L 3 CCMP, CREF, CSS 1 µF X7R 10% 25V MURATA GRM21BR71E105KA01L 1 CF 0.1 µF X7R 10% 25V MURATA GRM21BR71E104KA01L 0 CFS DNP 4 CIN 6.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 DESIGN #4 Bill of Materials Qty Part ID Part Value Manufacturer Part Number 1 LM3423 Boost controller TI LM3423MH 1 CBYP 2.2 µF X7R 10% 16V MURATA GRM21BR71C225KA12L 1 CCMP 1 µF X7R 10% 25V MURATA GRM21BR71E105KA01L 1 CFS 0.1 µF X7R 10% 25V MURATA GRM21BR71E104KA01L 4 CIN 4.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 DESIGN #5 Bill of Materials Qty Part ID Part Value Manufacturer Part Number 1 LM3421 Buck-boost controller TI LM3421MH 1 CB 100 pF COG/NPO 5% 50V MURATA GRM2165C1H101JA01D 1 CBYP 2.2 µF X7R 10% 16V MURATA GRM21BR71C225KA12L 1 CCMP 1 µF X7R 10% 25V MURATA GRM21BR71E105KA01L 1 CF 0.1 µF X7R 10% 25V MURATA GRM21BR71E104KA01L 0 CFS DNP 4 CIN 4.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com DESIGN #6 - LM3423 BUCK Application 15V ± 50V VIN 1 External Enable CIN 2 VIN LM3423 HSN HSP EN 20 RHSN 19 RHSP CFS RSNS RFS RT CCMP 3 COMP RPD 18 CO RPD RPU RCSH 4 5 CSH IS RCT VCC D2 17 ROV2 Q2 1.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 DESIGN #6 Bill of Materials Qty Part ID Part Value Manufacturer Part Number 1 LM3423 Buck controller TI LM3423MH 1 CBYP 2.2 µF X7R 10% 16V MURATA GRM21BR71C225KA12L 2 CCMP, CDIM 0.1 µF X7R 10% 25V MURATA GRM21BR71E104KA01L 0 CFS DNP 4 CIN 4.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com DESIGN #7 - LM3423 BUCK-BOOST Application L1 15V ± 60V VIN D1 Q2 RPU D2 1 CIN External Enable RT CCMP RCSH 2 3 4 VIN LM3423 HSN EN HSP COMP RPD IS CSH 20 RHSN 19 RHSP 18 2.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 DESIGN #7 Bill of Materials Qty Part ID Part Value Manufacturer Part Number 1 LM3423 Buck-boost controller TI LM3423MH 1 CBYP 2.2 µF X7R 10% 16V MURATA GRM21BR71C225KA12L 1 CCMP 0.33 µF X7R 10% 25V MURATA GRM21BR71E334KA01L 1 CFS 0.1 µF X7R 10% 25V MURATA GRM21BR71E104KA01L 4 CIN 4.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 www.ti.com SNVS574E – JULY 2008 – REVISED MAY 2013 DESIGN #8 Bill of Materials Qty Part ID Part Value Manufacturer Part Number 1 LM3421 SEPIC controller TI LM3421MH 1 CBYP 2.2 µF X7R 10% 16V MURATA GRM21BR71C225KA12L 1 CCMP 0.47 µF X7R 10% 25V MURATA GRM21BR71E474KA01L 0 CFS DNP 4 CIN 4.7 µF X7R 10% 100V TDK C5750X7R2A475K 4 CO 10 µF X7R 10% 50V TDK C4532X7R1H106K 1 CSEP 1.
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LM3421, LM3421-Q1 LM3423, LM3423-Q1 SNVS574E – JULY 2008 – REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Revision D (May 2013) to Revision E • 60 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 2-May-2013 Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) LM3421MHX/NOPB HTSSOP PWP 16 2500 330.0 12.4 LM3421Q0MHX/NOPB HTSSOP PWP 16 2500 330.0 LM3421Q1MHX/NOPB HTSSOP PWP 16 2500 330.0 LM3423MHX/NOPB HTSSOP PWP 20 2500 LM3423Q0MHX/NOPB HTSSOP PWP 20 LM3423Q1MHX/NOPB HTSSOP PWP 20 6.95 8.3 1.6 8.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM3421MHX/NOPB HTSSOP PWP 16 2500 367.0 367.0 35.0 LM3421Q0MHX/NOPB HTSSOP PWP 16 2500 367.0 367.0 35.0 LM3421Q1MHX/NOPB HTSSOP PWP 16 2500 367.0 367.0 35.0 LM3423MHX/NOPB HTSSOP PWP 20 2500 367.0 367.0 35.0 LM3423Q0MHX/NOPB HTSSOP PWP 20 2500 367.0 367.0 35.
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MECHANICAL DATA PWP0020A MXA20A (Rev C) www.ti.
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MECHANICAL DATA PWP0016A MXA16A (Rev A) www.ti.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.