Preliminary Datasheet LP6230 High Efficiency 2.5A/28V Boost DC/DC Convertor General Description Features The LP6230 is a current mode boost DC-DC converter. Its PWM circuitry with built-in 0.12Ω,28V,2.5A Current power MOSFET makes this converter highly power efficiently. Selectable high switching frequency allows faster loop response and easy filtering with a low noise output. The non-inverting input its error amplifier is connected to an internal 1.25V precision reference voltage. Soft-Start time can be programmed with an external capacitor, which sets the input current ramp rate. Current mode control and external compensation network make it easy and flexible to stabilize the system. Ordering Information LP6230 - □ □ Up to 94% efficiency Output to Input Disconnect at Shutdown Mode Shut-down current:<1uA Output voltage Up to 28V Internal Compensation 1.2MHz fixed frequency switching High switch on current:2.5A/30V Available in MSOP8 Package Applications Battery products Host Products Panel □ Pin Configurations F: Pb-Free Package Type MS: MSOP8 Typical Application Circuit Vin Vout_5V 4.7uH SS24 22uF 1uF 1 R3 100K 8 5 LX 22pF 2.2nF R1 100K Please see website:www.lowpowersemi.com. COMP SS 4 R4 7.5K Marking Information EN GND 3 VDD ON/OFF 6 1uF 22uF*2 FB 2 LP6230MSF R12 33K 3.3nF LP6230 –00 Ver. 1.0 Datasheet Dec.-2010 www.Lowpowersemi.com -- Page 1 of 7 Preliminary Datasheet LP6230 Functional Pin Description PIN PIN Name Description 1 2 COMP FB 3 EN 4 5 GND SW/LX 6 7 8 VIN FSEL/NC SS Error Amplifier Compensation Output. Regulation Feedback Input. Connect to an external resistive voltage divider from the output to FB to set the output voltage. Regulator On/off Control Input. A logic high input(VEN>1.4V) turns on the regulator. A logic low input(VEN<0.4V) puts the LP6230 into low current shutdown mode. Ground. Output switching node. SW is the drain of the internal low-side N-Channel MOSFET and high-side P-Channel MOSFET. Connect the inductor to SW to Complete the step-up converter. Power Supply pin. No Connector, The Frequency switching is 1.2MHz. Soft Star pin. Function Block Diagram LP6230 –00 Ver. 1.0 Datasheet Dec.-2010 www.Lowpowersemi.com -- Page 2 of 7 Preliminary Datasheet LP6230 Absolute Maximum Ratings Supply Input Voltage---------------------------------------------------------------------------------------------------------------6V Power Dissipation, PD @ TA = 25°C MSOP8----------------------------------------------------------------------------------------------------------900mW Package Thermal Resistance MSOP8, θJA ---------------------------------------------------------------------------------------------------------------165°C/W Lead Temperature (Soldering, 10 sec.) ----------------------------------------------------------------------------------260°C Recommended Operating Conditions Supply Input Voltage-------------------------------------------------------------------------------------------------2.2V to 6V EN Input Voltage -------------------------------------------------------------------------------------------------------0V to 5.5V Operation Junction Temperature Range ------------------------------------------------------------------−40°C to 125°C Operation Ambient TemperatureRange----------------------------------------------------------------------−40°C to 85°C Electrical Characteristics (Vin=2.4V,Vout=3.5V,Cin=10uF,Cout=22uF,L1=4.7uH,R1=178K,R2=100K) Parameter Conditions LP6230 Supply Voltage Min 2.2 Output Voltage Range 2.5 Typ Supply Current(Shutdown) VEN=VOUT=0V,VSW=5V 0.05 Supply Current VFB=1.3V 0.39 Feedback Voltage Feedback Input Current 1.22 VFB=1.2V Switching Frequency Maximum Duty Cycle 80 EN Input Low Voltage EN Input High Voltage 1.4 EN Pull Down Resistance Low-side On Resistance Vout=3.3V V 28 V 1 uA mA 1.28 V 50 nA 1200 KHz 90 95 % 0.4 V V 450 2.5 Vout=3.3V 30 Dec.-2010 A 120 Mosfet Voltage LP6230 –00 Ver. 1.0 Datasheet Max 5 1 Low-side Current Limit High-side On Resistance 1.25 Units www.Lowpowersemi.com -- Page 3 of 7 V Preliminary Datasheet LP6230 Typical Operating Characteristics LP6230 –00 Ver. 1.0 Datasheet Dec.-2010 www.Lowpowersemi.com -- Page 4 of 7 Preliminary Datasheet LP6230 –00 Ver. 1.0 Datasheet Dec.-2010 www.Lowpowersemi.com -- LP6230 Page 5 of 7 Preliminary Datasheet LP6230 Operation Information 100K resistor for R2 of the voltage divider. Determine the high-side resistor R1 by the equation: Vout=(R1/R2+1) X VFB Application Information Vout_24V Vin 4.7uH SS24 22uF 1uF 3 EN GND 8 SS LP6230 –00 Ver. 1.0 Datasheet Dec.-2010 2 4 FB LP6230MSF R2 33K 3.3nF Figure1. LP6230MSF Output 24V with Li-ion Battery Vout3_-10V Vout2_+20V 4.7uF 4.7uF 1uF Vin 1uF Vout1_10V 4.7uH SS14 22uF 1uF 22uF*2 1uF 1 8 R11 7.5K EN NC 7 22pF R9 600K COMP SS GND 3 R8 100K VDD ON/OFF LX 6 5 U24 2.2nF Setting the Output Voltage Set the output voltage by selecting the resistive voltage divider ratio. The voltage divider drops the output voltage to the 1.25V feedback voltage. Use a R1 600K 22pF COMP R4 7.5K 2.2nF 7 NC 1 R3 100K LX VDD ON/OFF 22uF*2 5 U23 6 1uF 4 The LP6230 uses a 640K/1200KHz fixed-frequency, current-mode regulation architecture to regulate the output voltage. The LP6230 measures the output voltage through an external resistive voltage divider and compares that to the internal 1.25V reference to generate the error voltage to the inductor current to regulate the output voltage.the use of current-mode regulation improves transient response and control loop stability.When the LP6230 is disable(EN=Low),both power switches are off. There is no current path from SW to OUT. There fore, the output voltage discharges to ground. When the LP6230 is enabled(EN=High),a limited start-current charges the output voltage rising to SW, then th part operates in force PWM mode for regulating the output voltage to the target value. At the beginning of each cycle, the N-channel MOSFET switch is turned on, forcing the inductor current to rise, The current at the source of the switch is internally measured and converted to a voltage by the current sense amplifier. That voltage is compared to the error voltage. When the inductor current rises sufficiently, the PWM comparator turns off the switch, forcing the inductor current to the output capacitor through the internal P-Channel MOSFET rectifier, which forces the inductor current to decrease. The peak inductor current is controlled by the error voltage. Thus the output voltage controls the inductor current to satisfy the lode. FB 2 LP6230MSF R10 33K 3.3nF Figure2. LP6230MSF For Panel application with Li-ion Battery www.Lowpowersemi.com -- Page 6 of 7 Preliminary Datasheet LP6230 Packaging Information LP6230 –00 Ver. 1.0 Datasheet Dec.-2010 www.Lowpowersemi.com -- Page 7 of 7