MCP1662T-E/OT

MCP1662 High-Voltage Step-Up LED Driver with UVLO and Open Load Protection Features General Description • • • • The MCP1662 device is a compact, space-efficient, fixed-frequency, non-synchronous step-up converter optimized to drive LED strings with constant current from a two- or three-cell alkaline or lithium Energizer®, or NiMH/NiCd, or one-cell Lithium-Ion or Li-Polymer batteries. • • • • • • • • • • 36V, 800 m Integrated Switch Up to 92% Efficiency Drive LED Strings in Constant Current 1.3A Peak Input Current Limit: - ILED up to 200 mA @ 5.0V VIN, 4 White LEDs - ILED up to 125 mA @ 3.3V VIN, 4 White LEDs - ILED up to 100 mA @ 4.2V VIN, 8 White LEDs Input Voltage Range: 2.4V to 5.5V Feedback Voltage Reference: VFB = 300 mV Undervoltage Lockout (UVLO): - UVLO @ VIN Rising: 2.3V, typical - UVLO @ VIN Falling: 1.85V, typical Sleep Mode with 20 nA Typical Quiescent Current PWM Operation: 500 kHz Switching Frequency Cycle-by-Cycle Current Limiting Internal Compensation Open Load Protection (OLP) in the Event of: - Feedback pin shorted to GND (prevent excessive current into LEDs) - Disconnected LED string (prevent overvoltage to the converter’s Output and SW pin) Overtemperature Protection Available Packages: - 5-Lead SOT-23 - 8-Lead 2x3 TDFN The device integrates a 36V, 800 m low-side switch, which is protected by the 1.3A cycle-by-cycle inductor peak current limit operation. All compensation and protection circuitry is integrated to minimize the number of external components. The internal feedback (VFB) voltage is set to 300 mV for low power dissipation when sensing and regulating the LED current. A single resistor sets the LED current. The device features an Undervoltage Lockout (UVLO) that avoids start-up with low inputs or discharged batteries for two-cell-powered applications. There is an open load protection (OLP) which turns off the operation in situations when the LED string is accidentally disconnected or the feedback pin is short-circuited to GND. For standby applications (EN = GND), the device stops switching, enters into Sleep mode and consumes 20 nA typical of input current. Package Types MCP1662 SOT-23 Applications • Two and Three-Cell Alkaline or NiMH/NiCd White LED Driver for Backlighting Products • Li-Ion Battery LED Lighting Application • Camera Flash • LED Flashlights and Backlight Current Source • Medical Equipment • Portable Devices: - Handheld Gaming Devices - GPS Navigation Systems - LCD Monitors - Portable DVD Players SW 1 5 VIN GND 2 VFB 3 4 EN MCP1662 2x3 TDFN* VFB 1 SGND 2 SW 3 NC 4 8 EN EP 9 7 PGND 6 NC 5 V IN * Includes Exposed Thermal Pad (EP); see Table 3-1.  2014-2015 Microchip Technology Inc. DS20005316E-page 1 MCP1662 Typical Application D MBR0540 L 4.7 – 10 µH VOUT LED1 CIN 4.7 – 30 µF VIN 2.4V – 3.0V SW LED2 VIN + ALKALINE ILED = LED6 EN VFB ON ALAKLINE COUT 10 µF MCP1662 - + 0.3V RSET OFF GND VFB = 0.3V RSET 12 ILED = 25 mA - L = 4.7 µH for maximum 4 white LEDs L = 10 µH for 5 to 10 white LEDs CIN = 4.7-10 µF for VIN > 2.5V CIN = 20-30 µF for VIN < 2.5V Maximum LED Current in Regulation vs. Input Voltage, TA = + 25°C 250 4 wLEDs, L = 4.7 µH IOUT LED (mA) 200 150 8 wLEDs, L = 10 µH 100 50 0 2 DS20005316E-page 2 2.5 3 3.5 4 VIN (V) 4.5 5 5.5  2014-2015 Microchip Technology Inc. MCP1662 1.0 ELECTRICAL CHARACTERISTICS † Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational sections of this specification is not intended. Exposure to maximum rating conditions for extended periods may affect device reliability. Absolute Maximum Ratings † VSW – GND .....................................................................+36V EN, VIN – GND...............................................................+6.0V VFB ...............................................................................+0.35V Power Dissipation ....................................... Internally Limited Storage Temperature .................................... -65°C to +150°C Ambient Temperature with Power Applied .... -40°C to +125°C Operating Junction Temperature................... -40°C to +150°C ESD Protection on All Pins: HBM ................................................................. 4 kV MM ..................................................................300V DC AND AC CHARACTERISTICS Electrical Specifications: Unless otherwise specified, all limits apply for typical values at ambient temperature TA = +25°C, VIN = 3.3V, VOUT = 9V or 3 white LEDs (VF = 2.75V @ IF = 20 mA or VF = 3.1V @ IF = 100 mA), ILED = 20 mA, CIN = COUT = 10 µF, X7R ceramic, L = 4.7 µH. Boldface specifications apply over the controlled TA range of -40°C to +125°C. Parameters Sym. Min. Typ. Max. Units VIN 2.4 — 5.5 V UVLOSTART — 2.3 — V VIN rising, ILED = 20 mA UVLOSTOP — 1.85 — V VIN falling, ILED = 20 mA Maximum Output Voltage VOUTmax — — 32 V Maximum Output Current IOUT — 100 — mA 4.2V VIN, 8 LEDs 125 — mA 3.3V VIN, 4 LEDs 200 — mA 5.0V VIN, 4 LEDs Input Voltage Range Undervoltage Lockout (UVLO) Feedback Voltage Reference Conditions Note 1 VFB 275 300 325 mV VFB_OLP — 50 — mV Feedback Input Bias Current IVFB — 0.005 — µA Shutdown Quiescent Current IQSHDN — 0.02 — µA EN = GND IN(MAX) — 1.3 — A Note 2 INLK — 0.4 — µA VIN = VSW = 5V; VOUT = 5.5V VEN = VFB = GND RDS(ON) — 0.8 —  VIN = 5V, ILED = 100 mA, 4 series white LEDs (Note 2) |(VFB/VFB)/VIN| — 0.25 — %/V Feedback Open Load Protection (OLP) Threshold NMOS Peak Switch Current Limit NMOS Switch Leakage NMOS Switch ON Resistance Feedback Voltage Line Regulation VFB falling (Note 2) VIN = 3.0V to 5V Maximum Duty Cycle DCMAX — 90 — % Note 2 Switching Frequency fSW 425 500 575 kHz ±15% EN Input Logic High VIH 85 — — % of VIN Note 1: 2: Minimum input voltage in the range of VIN (VIN < 5.5V < VOUT) depends on the maximum duty cycle (DCMAX) and on the output voltage (VOUT), according to the boost converter equation: VINmin = VOUT x (1 – DCMAX). Output voltage is equal to the LED voltage plus the voltage on the sense resistor (VOUT = VLED + V_RSET). Determined by characterization, not production tested.  2014-2015 Microchip Technology Inc. DS20005316E-page 3 MCP1662 DC AND AC CHARACTERISTICS (CONTINUED) Electrical Specifications: Unless otherwise specified, all limits apply for typical values at ambient temperature TA = +25°C, VIN = 3.3V, VOUT = 9V or 3 white LEDs (VF = 2.75V @ IF = 20 mA or VF = 3.1V @ IF = 100 mA), ILED = 20 mA, CIN = COUT = 10 µF, X7R ceramic, L = 4.7 µH. Boldface specifications apply over the controlled TA range of -40°C to +125°C. Parameters Sym. Min. Typ. Max. Units VIL — — 7.5 % of VIN IENLK — 0.025 — µA VEN = 5V Start-up Time tSS — 100 — µs EN Low-to-High, 90% of ILED (Note 2, Figure 2-10) Thermal Shutdown Die Temperature TSD — 150 — °C TSDHYS — 15 — °C EN Input Logic Low EN Input Leakage Current Die Temperature Hysteresis Note 1: 2: Conditions Minimum input voltage in the range of VIN (VIN < 5.5V < VOUT) depends on the maximum duty cycle (DCMAX) and on the output voltage (VOUT), according to the boost converter equation: VINmin = VOUT x (1 – DCMAX). Output voltage is equal to the LED voltage plus the voltage on the sense resistor (VOUT = VLED + V_RSET). Determined by characterization, not production tested. TEMPERATURE SPECIFICATIONS Electrical Specifications: Unless otherwise specified, all limits apply for typical values at ambient temperature TA = +25°C, VIN = 3.0V, IOUT = 20 mA, VOUT = 12V, CIN = COUT = 10 µF, X7R ceramic, L = 4.7 µH. Boldface specifications apply over the air-forced TA range of -40°C to +125°C. Parameters Sym. Min. Typ. Max. Units Operating Junction Temperature Range TJ -40 — +125 °C Storage Temperature Range TA -65 — +150 °C Maximum Junction Temperature TJ — — +150 °C Thermal Resistance, 5L-SOT-23 JA — 201.0 — °C/W Thermal Resistance, 8L 2x3 TDFN JA — 52.5 — °C/W Conditions Temperature Ranges Steady State Transient Package Thermal Resistances DS20005316E-page 4  2014-2015 Microchip Technology Inc. MCP1662 2.0 TYPICAL PERFORMANCE CURVES Note: The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. Note: Unless otherwise indicated: VIN = 3.3V, ILED = 20 mA, VOUT = 12V or 4 white LEDs (VF = 2.75V @ IF = 20 mA or VF = 3.1V @ IF = 100 mA), CIN = COUT = 10 µF, X7R ceramic, L = 4.7 µH. 150 100 4 x wLED, L = 4.7 µH RSET = 2.2ȍ 80 Efficiency (%) LED Current (mA) VIN = 5.5V 90 125 RSET = 3.2ȍ 100 75 RSET = 6.2ȍ 50 VIN = 4.0V 70 60 VIN = 3.0V 50 40 30 25 L = 4.7 µH, 4 wLEDs 20 RSET = 15ȍ 10 0 0 2.3 2.7 FIGURE 2-1: 3.1 3.5 3.9 4.3 Input Voltage (V) 4.7 5.1 5.5 4 White LEDs, ILED vs. VIN. 0 50 75 100 125 150 175 200 225 250 ILED (mA) FIGURE 2-4: ILED. 4 White LEDs, Efficiency vs. 100 120 4 x wLED, L = 4.7 µH, VIN = 3.3V 90 RSET = 3.2ȍ 80 60 RSET = 6.2ȍ 40 80 Efficiency (%) 100 LED Current (mA) 25 VIN = 5.5V 70 VIN = 3.0V VIN = 4.0V 60 50 40 30 RSET = 15ȍ 20 L = 10 µH, 8 wLEDs 20 10 0 0 -40 -25 -10 FIGURE 2-2: 4 White LEDs, ILED vs. Ambient Temperature. 40 60 80 100 ILED (mA) 120 140 160 8 White LEDs, Efficiency vs. 300 8 x wLED, L = 10 µH, VIN = 4.2V 250 RSET = 3.2ȍ 100 LED Current (mA) 20 FIGURE 2-5: ILED. 80 60 RSET = 6.2ȍ 40 RSET = 15ȍ 20 LED Current (mA) 120 0 5 20 35 50 65 80 95 110 125 Ambient Temperature (oC) 200 2 wLEDs, L = 4.7 µH 150 5 wLEDs, L = 10 µH 4 wLEDs, L = 4.7 µH 100 8 wLEDs, L = 10 µH 50 0 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 Ambient Temperature (oC) FIGURE 2-3: 8 White LEDs, ILED vs. Ambient Temperature.  2014-2015 Microchip Technology Inc. 2.3 2.7 FIGURE 2-6: 3.1 3.5 3.9 4.3 Input Voltage (V) 4.7 5.1 5.5 Maximum ILED vs. VIN. DS20005316E-page 5 MCP1662 Note: Unless otherwise indicated: VIN = 3.3V, ILED = 20 mA, VOUT = 12V or 4 white LEDs (VF = 2.75V @ IF = 20 mA or VF = 3.1V @ IF = 100 mA), CIN = COUT = 10 µF, X7R ceramic, L = 4.7 µH. 2.5 250 UVLO Start 2.3 Blue Bars - ILED = 20 mA Red Bars - ILED = 40 mA 200 2.2 2.1 2 UVLO Stop 1.9 1.8 1.7 Start-up Time (µs) UVLO Thresholds (V) 2.4 150 100 50 1.6 0 1.5 -40 -25 -10 5 3 20 35 50 65 80 95 110 125 Ambient Temperature 4 5 6 Number of LEDs 7 8 (oC) FIGURE 2-7: Undervoltage Lockout (UVLO) vs. Ambient Temperature. FIGURE 2-10: of LEDs. Soft Start Time vs. Number 50 3 LEDs, ILED = 20 mA Shutdown Iq (nA) 40 ILED 10 mA/div 30 20 VEN 2V/div 10 VIN 2V/div 0 2.2 2.5 2.8 3.1 3.4 3.7 4.0 4.3 4.6 4.9 5.2 5.5 Input Voltage (V) FIGURE 2-8: Shutdown Quiescent Current, IQSHDN, vs. VIN (EN = GND). 40 µs/div FIGURE 2-11: VIN = VENABLE. Start-Up When Switching Frequency (kHz) 550 3 LED, ILED = 20 mA 525 ILED 10 mA/div 500 VEN 2V/div 475 VIN 2V/div 450 -40 -25 -10 5 20 35 50 65 80 95 110 125 Ambient Temperature (°C) FIGURE 2-9: Switching Frequency, fSW vs. Ambient Temperature. DS20005316E-page 6 40 µs/div FIGURE 2-12: Start-Up After Enable.  2014-2015 Microchip Technology Inc. MCP1662 Note: Unless otherwise indicated: VIN = 3.3V, ILED = 20 mA, VOUT = 12V or 4 white LEDs (VF = 2.75V @ IF = 20 mA or VF = 3.1V @ IF = 100 mA), CIN = COUT = 10 µF, X7R ceramic, L = 4.7 µH. 3 LEDs 3 LEDs VOUT 3V/div ILED 10 mA/div VSW 4V/div VSW 4V/div ILED 20 mA/div VEN 3V/div 1 µs/div 2 ms/div FIGURE 2-13: Duty Cycle. 100 Hz PWM Dimming, 15% FIGURE 2-16: 3.3V Input, 20 mA 3 White LEDs PWM Discontinuous Mode Waveforms. 3 LEDs 3 LEDs ILED 100 mA/div VOUT 3V/div VSW 4V/div ILED 50 mA/div VSW 4V/div VEN 3V/div 1 µs/div 2 ms/div FIGURE 2-14: Duty Cycle. 100 Hz PWM Dimming, 85% FIGURE 2-17: 3.3V Input, 100 mA 3 White LEDs PWM Continuous Mode Waveforms. 3 LEDs VFB 300 mV/div ILED 10 mA/div VSW 4V/div 50 ms/div FIGURE 2-15: Open Load (LED Fail or FB to GND) Response.  2014-2015 Microchip Technology Inc. DS20005316E-page 7 MCP1662 3.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table 3-1. TABLE 3-1: 3.1 PIN FUNCTION TABLE MCP1662 SOT-23 MCP1662 2x3 TDFN 3 1 VFB — 2 SGND Symbol Description Feedback Voltage Pin Signal Ground Pin 1 3 SW Switch Node, Boost Inductor Input Pin — 4, 6 NC Not Connected Input Voltage Pin 5 5 VIN — 7 PGND Power Ground Pin 4 8 EN Enable Control Input Pin — 9 EP Exposed Thermal Pad (EP); must be connected to Ground 2 — GND Ground Pin Feedback Voltage Pin (VFB) The VFB pin is used to regulate the voltage across the RSET sense resistor to 300 mV to keep the output LED current in regulation. Connect the cathode of the LED to the VFB pin. 3.2 Signal Ground Pin (SGND) The signal ground pin is used as a return for the integrated reference voltage and error amplifier. The signal ground and power ground must be connected externally in one point. 3.3 Switch Node Pin (SW) Connect the inductor from the input voltage to the SW pin. The SW pin carries inductor current and has a typical value of 1.3A peak. The integrated N-Channel switch drain is internally connected to the SW node. 3.4 Not Connected (NC) 3.7 Enable Pin (EN) The EN pin is a logic-level input used to enable or disable device switching and lower quiescent current while disabled. A logic high (>85% of VIN) will enable the regulator output. A logic low ( 4 !/  ; : = 4 !