UNISONIC TECHNOLOGIES CO., LTD US2651 Preliminary CMOS IC HIGH PRECISION LOW COST MCM POWER SWITCH DESCRIPTION DIP-8 The UTC US2651 is a high performance, high precision and low cost PWM Power switch for non-isolated buck application. It combines a dedicated current mode PWM controller and error amplifier for low component count. UTC US2651 use UTC proprietary frequency shuffling technique for EMI performance. And oscillator with frequency-reduction control is implemented. The UTC US2651 has soft start control and protection function, such as Cycle-by-Cycle current limiting, Over Loading Protection, Output Short-Circuit Protection, RCS short Protection, OTP, VDD OVP, and UVLO. SOP-8 FEATURES * Power on soft-start * Load compensation * Built-in error amplifier * Oscillator of fixed frequency with frequency-reduction control * Frequency shuffling for EMI improvement * Built-in Leading Edge Blanking (LEB) * Cycle-by-Cycle current limiting * Over loading protection * Output short-circuit protection * VDD Under Voltage Lockout with hysteresis (UVLO) * VDD OVP ORDERING INFORMATION Ordering Number Lead Free Halogen Free US2651L-D08-T US2651G-D08-T US2651G-S08-R Package Packing DIP-8 SOP-8 Tube Tape Reel US2651L-D08-T (1)Packing Type (1) T: Tube, R: Tape Reel (2)Package Type (2) D08: DIP-8, S08: SOP-8 (3)Green Package (3) L: Lead Free, G: Halogen Free and Lead Free www.unisonic.com.tw Copyright © 2014 Unisonic Technologies Co., Ltd 1 of 6 QW-R502-B23.b US2651 Preliminary CMOS IC MARKING DIP-8 PIN CONFIGURATION PIN DESCRIPTION PIN NO. 1 2 3 4 PIN NAME VDD COMP NC CS 5, 6 DRAIN 7, 8 GND SOP-8 DESCRIPTION Power supply Loop compensation for CV stability Not connected Current sense input HV MOSFET Drain Pin. The Drain pin is connected to the primary lead of the transformer/ inductance. Ground UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 6 QW-R502-B23.b US2651 Preliminary CMOS IC BLOCK DIAGRAM UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 3 of 6 QW-R502-B23.b US2651 Preliminary CMOS IC ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS UNIT Drain Voltage (Off State) BVDSS -0.3~BVdss V VDD Voltage -0.3~40 V VDD Zenzer Clamp Continuous Current IDD 10 mA COMP Voltage VCOMP -0.3~7 V CS Input Voltage VCS -0.3~7 V Operating Junction Temperature TJ -40~150 °C Storage Temperature TSTG -55~150 °C Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. THERMAL CHARACTERISTICS PARAMETER Junction to Ambient SYMBOL DIP-8 SOP-8 θJA RATINGS 75 90 UNIT °C/W °C/W ELECTRICAL CHARACTERISTICS (TA=25°C, VDD=16V, if not otherwise noted) PARAMETER SYMBOL SUPPLY VOLTAGE (VDD) SECTION Standby Current IDD ST Operation Current IDD OP VDD Under Voltage Lockout Enter UVLO(ON) VDD Under Voltage Lockout Exit UVLO (OFF) Over Voltage Protection OVP Threshold In Normal Regulation, VDD will be VDD Regulated to 19.3V CURRENT SENSE INPUT SECTION LEB Time TLEB Over Current Threshold VTH_OC OCP Propagation Delay TD_OC Input Impedance ZSENSE_IN FREQUENCY SECTION IC Maximum Frequency Freq_MAX Frequency Shuffling Range △f/Freq ERROR AMPLIFIER SECTION DC Gain of EA Gain Max. Cable Compensation I_COMP_MAX Current POWER MOSFET SECTION MOSFET Drain-Source BVDSS Breakdown Voltage On Resistance RDS(ON) TEST CONDITIONS VDD= UVLO (OFF)-0.1V Operation Supply Current CS=0V, VDD=18V VDD Falling VDD Rising TYP MAX UNIT 35 μA 3.0 mA 7 12 8 13 9 14 V V Ramp VDD Until Gate Shut Down 24.5 25.5 26.5 V Ramp VDD Until Comp Voltage Lower than 2.5V 18.5 19.3 20.5 V 750 300 860 110 970 40 40 VDD=18V, COMP=0V 50 ±6 60 Static, ID=0.45A ns mV ns KΩ KHz % 60 dB 6 μA 600 UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw MIN V 15 Ω 4 of 6 QW-R502-B23.b US2651 Preliminary CMOS IC OPERATION DESCRIPTION The UTC US2651 is a cost effective PWM power switch optimized for off-line non-isolated buck applications including electrical appliance and linear regulator replacement. It operates in current mode and regulates output voltage with dedicated features. High integration can afford low cost and component count solution. Startup Current and Start up Control Startup current of UTC US2651 is designed to be very low so that VDD could be charged up above UVLO threshold and starts up quickly. A large value startup resistor can therefore be used to minimize the power loss in application. Operating Current The Operating current of UTC US2651 is as low as 3mA. Good efficiency is achieved with the low operating current together with ‘Muti-mode’ control features. Oscillator operationF The switching frequency of UTC US2651 is internally fixed at 50KHZ. No external frequency setting components are required for PCB design simplification. At light load or zero load condition, most of the power dissipation in a switching mode power supply is from switching loss on the MOSFET. The magnitude of power loss is in proportion to the switching frequency. Lower switching frequency leads to the reduction on the power loss and thus conserves the energy. The switching frequency is internally adjusted at light load or no load condition. The switch frequency reduces at light/no load condition to improve the conversion efficiency. The minimum switching frequency is 400Hz. Frequency shuffling for EMI improvement The frequency shuffling (switching frequency modulation) is implemented in UTC US2651. The oscillation frequency is modulated so that the tone energy is spread out. The spread spectrum minimizes the conduction band EMI and therefore eases the system design. Built-in error amplifier In UTC US2651, on-chip EA (error amplifier) is implemented to regulate output voltage. Through inner resistor divider, the VDD voltage is detected at inverter input of EA to regulate output voltage. Load Compensation for good CV regulation In UTC US2651, load compensation is implemented to achieve good load regulation. An offset voltage is generated at inverter input of EA by an internal current flowing into the resister divider. The current is inversely proportional to the voltage across pin COMP, as a result, it is inversely proportional to the output load current, thus the output voltage can be compensated specially in zero loading condition. As the load current decreases from full-load to no-load, the offset voltage at inverter input of EA will increase. Current Sensing and Leading Edge Blanking Cycle-by-Cycle current limiting is offered in UTC US2651 current mode PWM control. The switch current is detected by a sense resistor into the CS pin. An internal leading edge blanking circuit chops off the sensed voltage spike at initial internal power MOSFET on state so that the external RC filtering on sense input is no longer needed. The PWM duty cycle is determined by the current sense input voltage and the EA output voltage. Gate Drive The internal power MOSFET in UTC US2651 is driven by a dedicated gate driver for power switch control. Too weak the gate drive strength results in higher conduction and switch loss of MOSFET while too strong gate drive compromises EMI. A good tradeoff is achieved through the built-in totem pole gate design with right output strength control. Protection Control Good power supply system reliability is achieved with its rich protection features including Cycle-by Cycle current limiting (OCP), Over Loading Protection, Over Voltage Protection, Output Short-Circuit Protection and Under Voltage Lockout on VDD (UVLO). UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5 of 6 QW-R502-B23.b US2651 Preliminary CMOS IC TYPICAL APPLICATION CIRCUIT ES1G UTC US2651 47nF 510K 2Ω 510K VDD GND 8 2 COMP GND 7 1 3 NC DRAIN 6 4 CS DRAIN 5 10μF 1mH 19V/0.25A ES1G AC IN 10μF 470μF DC OUT UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 6 of 6 QW-R502-B23.b