HX6291

HX6291 1MHz, 2.5A Step-Up Current Mode PWM Converter General Description The HX6291 is a current mode boost DC-DC converter. Its PWM circuitry with built-in 0.2Ω power MOSFET make this regulator highly power efficient. The internal compensation network also minimizes as much as 6 external component counts. The non-inverting input of error amplifier connects to a 0.6V precision reference voltage and internal soft-start function can reduce the inrush current. The HX6291 is available in the SOT23-6L package and provides space-saving PCB for the application fields. Features  Adjustable Output up to 12V  Internal Fixed PWM frequency: 1.0MHz  Precision Feedback Reference Voltage: 0.6V (±2%)  Internal 0.2Ω, 2.5A, 16V Power MOSFET  Shutdown Current: 0.1μA  Over Temperature Protection  Over Voltage Protection  Adjustable Over Current Protection: 0.5A ~ 2.5A  Package: SOT23-6L Applications  Chargers  LCD Displays  Digital Cameras  Handheld Devices  Portable Products Typical Application Circuit 4 FB EN HX6291 5 6 VCC GND OC LX 3 2 1 VIN 1/9 VOUT HX6291 Function Block Diagram VCC GND EN OC Shutdown Circuitry UVLO Adjustable Current Limit 19kΩ ~ 96 kΩ 2.5 A ~0.5A LX OTP OVP Error Amp .. FB Control and Driver Logic 0.6V PWM Comp. Soft Start PGND Current Sense Amp. Slope Compensation Oscillator 1 MHz Pin Descriptions SOT23-6L Name Top View GND 2 FB 3 AL986 LX 1 6 OC 5 VCC 4 EN No. I / O Description LX 1 O Power Switch Output GND 2 P IC Ground FB 3 I Error Amplifier Inverting Input EN 4 I Enable Control (Active High) VCC 5 P IC Power Supply OC 6 I Adjustable Current Limit Marking Information SOT23-6L AL986 Lot Number Year Part Number Code Lot Number: Wafer lot number’s last two digits For Example: 132386TB  86 Year: Production year’s last digit Part Number Code: Part number identification code for this product. It should be always “AL”. 2/9 HX6291 Ordering Information Part Number Code HX6291 AL Operating Temperature Package MOQ Description -40°C ~ 85°C SOT23-6L 3000EA Tape & Reel Absolute Maximum Ratings Parameter Symbol Conditions Min. Typ. Max. Unit Supply Voltage VCC 0 6 V LX Voltage VLX 0 16 V 0 6 V EN,FB Voltage Power Dissipation PD SOT23-6L @TA=25°C 455 mW Thermal Resistance (Note1) θJA SOT23-6L +220 °C / W Junction Temperature TJ +150 °C Operating Temperature TOP -40 +85 °C Storage Temperature TST -65 +150 °C +260 °C Lead Temperature (soldering, 10 sec) Note1: θJA is measured in the natural convection at T A=25°C on a low effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard. IR Re-flow Soldering Curve 3/9 HX6291 Recommended Operating Conditions Parameter Symbol Supply Voltage VIN Operating Temperature Range TA Conditions Ambient Temperature Min. Max. Unit 2.6 Typ. 5.5 V -40 +85 °C DC Electrical Characteristics (VCC=3.3V, TA=25°C,unless otherwise specified) Parameter Symbol Conditions Min. Typ. Max. Unit 5.5 V System Supply Input Input Supply Range Under Voltage Lockout VCC 2.6 VUVLO 2.2 UVLO Hysteresis V 0.1 V Quiescent Current ICC VFB=0.66V, No switching 0.19 mA Average Supply Current ICC VFB=0.55V, Switching 2.84 mA Shutdown Supply Current ICC VEN=GND 0.1 µA FOSC VFB=1.0V Oscillator Operation Frequency Frequency Change with Voltage Maximum Duty Cycle 0.8 △ f / △ V VCC=2.6V to 5.5V TDUTY 1.0 1.2 MHZ 5 % 90 % Reference Voltage Reference Voltage VREF Line Regulation 0.588 0.6 0.612 0.2 VCC=2.6V～5.5V V %/V Enable Control Enable Voltage VEN Shutdown Voltage VEN 0.96 V 0.6 V MOSFET On Resistance of Driver RDS (ON) ILX=2A 0.2 Ω 2.5 A Protection OCP Current IOCP Adjustable OCP Current IOCP OTP Temperature TOTP With External Resistor： 19k~96k 2.5 0.5 +150 4/9 A °C HX6291 Typical Operating Characteristics (VCC=3.3V, VOUT=5V, TA= 25°C, unless otherwise noted) Current Limit vs. External Resistance (Roc) Efficiency vs. Output Current 3.5 100 3 95 2.5 Current Limit (A) Efficiency (%) 90 85 80 2 1.5 1 75 0.5 70 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10 1 20 30 40 Freqency (MHz) Operation Frequency vs. Input Voltage 1.16 60 1.14 1.12 1.1 1.08 1.06 1.04 4 90 100 5 vs. T emperature 1.08 1.06 1.04 1.02 VIN =5V, VOUT =9V 1 3 80 Operation Frequency 1.02 2 70 1.1 Operation Operation Frequency (MHz) 50 External Resistance (kΩ) Output Current (A) 6 -40 -20 0 Input Voltage (V) 20 40 60 80 100 T e m p e r a t u r e ( °C ) Reference Voltage vs. Input Voltage Reference Voltage vs. Output Current 0.607 0.605 Feedback Voltage (V) Feedback Voltage (V) 0.606 0.605 0.604 0.603 0.602 0.601 0.604 0.603 0.602 0.601 0.6 0.6 2 3 4 5 6 0 0.1 0.2 0.3 Input Voltage (V) Quiescent Current vs. Input Voltage 0.5 0.6 0.7 0.8 0.9 1 Average Supply Current vs. Input Voltage 270 4.5 Average Supply Current (mA) Quiescent Current (uA) 0.4 Output Current (A) 240 210 180 150 120 4 3.5 3 2.5 2 1.5 1 0.5 2 3 4 5 6 2 Input Voltage (V) 3 4 Input Voltage (V) 5/9 5 6 HX6291 Function Description Operation The HX6291 is a current mode boost converter. The constant switching frequency is 1MHz and operates with pulse width modulation (PWM). Build-in 16V / 2.5A MOSFET provides a high output voltage. The control loop architecture is peak current mode control; therefore slope compensation circuit is added to the current signal to allow stable operation for duty cycles larger than 50%. Soft Start Function Soft start circuitry is integrated into HX6291 to avoid inrush current during power on. After the IC is enabled, the output of error amplifier is clamped by the internal soft-start function, which causes PWM pulse width increasing slowly and thus reducing input surge current. Current Limit Program A resistor between OC and GND pin programs peak switch current. The resistor value should be between 19k and 96k. The current limit will be set from 2.5A to 0.5A. Keep traces at this pin as short as possible. Do not put capacitance at this pin. To set the over current trip point according to the following equation: IOCP  48000 R3 Over Temperature Protection (OTP) HX6291 will turn off the power MOSFET automatically when the internal junction temperature is over 150°C. The power MOSFET wake up when the junction temperature drops 30 °C under the OTP threshold temperature. Over Voltage Protection (OVP) In some condition, the resistive divider may be unconnected, which will cause PWM signal to operate with maximum duty cycle and output voltage is boosted higher and higher. The power MOSFET will be turned off immediately, when the output voltage exceeds the OVP threshold level. The HX6291’s OVP threshold is 16V. 6/9 HX6291 Application Information Inductor Selection Inductance value is decided based on different condition. 3.3uH to 4.7µH inductor value is recommended for general application circuit. There are three important inductor specifications, DC resistance, saturation current and core loss. Low DC resistance has better power efficiency. Also, it avoid inductor saturation which will cause circuit system unstable and lower core loss at 1 MHz. Capacitor Selection The output capacitor is required to maintain the DC voltage. Low ESR capacitors are preferred to reduce the output voltage ripple. Ceramic capacitor of X5R and X7R are recommended, which have low equivalent series resistance (ESR) and wider operation temperature range. Diode Selection Schottky diodes with fast recovery times and low forward voltages are recommended. Ensure the diode average and peak current rating exceed the average output current and peak inductor current. In addition, the diode’s reverse breakdown voltage must exceed the output voltage. Output Voltage Programming The output voltage is set by a resistive voltage divider from the output voltage to FB. The output voltage is: R1   VOUT  0.6V1    R2  Layout Considerations 1. The power traces, consisting of the GND trace, the LX trace and the VCC trace should be kept short, direct and wide. 2. LX、L and D switching node, wide and short trace to reduce EMI. 3. Place CIN near VCC pin as closely as possible to maintain input voltage steady and filter out the pulsing input current. 4. The resistive divider R1and R2 must be connected to FB pin directly as closely as possible. 5. FB is a sensitive node. Please keep it away from switching node, LX. 6. The GND of the IC, CIN and COUT should be connected close together directly to a ground plane. 7/9 HX6291 C1 GND Vin R2 C3 C2 C4 R1 4 3 5 R3 HX6291 Vout 1 6 VIA to GND 2 D1 L1 Suggested Layout Typical Application 4 FB EN HX6291 5 6 VCC GND OC LX 3 2 VOUT 1 R3 20K D1 SM340A L1 3.3µH R2 12K VIN 5V R1 88K C2 20µF C4 0.1µF 3.7V C3 0.1µF C1 20µF Note: 1. Don’t pull the Vout back to the HX6291’s Vcc pin. When the system receives the noise, it will lead to Vout ripple too high and over the absolute maximum rating of the Vcc pin. 2. EN voltage must be less than or equal to Vcc voltage. 8/9 HX6291 Package Outline SOT23-6L Unit: mm Symbols Min. (mm) Max. (mm) A 1.050 1.450 A1 0.050 0.150 A2 0.900 1.300 b 0.300 0.500 c 0.080 0.220 D 2.900 BSC E 2.800 BSC E1 1.600 BSC e 0.950 BSC e1 1.900 BSC L 0.300 0.600 L1 0.600 REF L2 0.250 BSC θ° 0° 8° θ1° 3° 7° θ2° 6° 15° Note: 1. Package dimensions are in compliance with JEDEC outline: MO-178 AB. 2. Dimension “D” does not include molding flash, protrusions or gate burrs. 3. Dimension “E1” does not include inter-lead flash or protrusions. 9/9