(RT9241A/B) 2-Phase DC/DC Controller

www.DataSheet4U.com RT9241A/B Two-Phase DC/DC Controller for CPU Core Power Supply General Description The RT9241A/B is a two-phase buck DC/DC controller integrated with all control functions for high performance processor VRM. The RT9241A/B drives 2 buck switching stages operating in 180 degree phase shift. The two-phase architecture provides high output current while maintaining low power dissipation on power devices and low stress on input and output capacitors. The high equivalent operating frequency also reduces the component dimension and the output voltage ripple in load transient. RT9241A/B regulates both easily set voltage and current loops. Precise current sharing for power stage is achieved by differential input current sense and processing circuit. The settings of current sense, droop tuning and over current protection are independent to compensation circuit of voltage loop. The feature greatly facilitates the flexibility of CPU power supply design and tuning. The RT9241A/B uses a 5-bit DAC of 1.1V to 1.85V (25mV/step) output with load current droop compensation to meet the strict VRM transient requirement. The IC monitors the VCORE voltage for PGOOD and over voltage protection. Soft start, over current protection and programmable under voltage lockout are also provided to assure the safety of microprocessor and power system. Features Two-Phase Power Conversion VRM 9.0 DAC Output with Active Droop Compensation for Fast Load Transient Precise Channel Current Sharing with Differential Sense Input Hiccup Mode Over Current Protection Programmable Under Voltage Lockout and Soft Start High Ripple Frequency, (Channel Frequency Times Channel Number) 100KHz Version (RT9241B) for Lower Switching Loss Applications Power Supply for Server and Workstation Power Supply for High Current Microprocessor Pin Configurations Part Number RT9241A/B CS (Plastic SOP-20) VID4 VID3 VID2 VID1 VID0 COMP FB ADJ DVD SS 1 2 3 4 5 6 7 8 9 10 Pin Configurations TOP VIEW 20 19 18 17 16 15 14 13 12 11 VDD PGOOD ISP1 PWM1 PWM2 ISP2 VSEN GND ISN1 ISN2 Ordering Information RT9241A/B Package type S : SOP-20 Operating temperature range C: Commercial standard Operating frequency version A : 200KHz B : 100KHz DS9241AB-01 October 2002 www.richtek.com 1 www.DataSheet4U.com RT9241A/B Absolute Maximum Ratings Supply Voltage Input, Output or I/O Voltage Power Dissipation, PD @ TA = 25°C SOP-20 Package Thermal Resistance SOP-20, θJA Ambient Temperature Range Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering, 10 sec.) 7V GND-0.3V ~ VDD+0.3V 0.625W 110°C /W 0°C ~ 70°C 0°C ~ 125°C -40°C ~ 150°C 260°C Electrical Characteristics (VDD = 5V, GND = 0V, TA = 25°C, unless otherwise specified) Parameter VDD Supply Current Nominal Supply Current Power-On Reset VDD Rising Threshold VDD Falling Threshold Hysteresis VDVD Rising Trip Threshold Oscillator Frequency Ramp Amplitude Ramp Valley Maximum On Time of Each Channel Reference and DAC DACOUT Voltage Accuracy DAC (VID0-VID4) Input Low Voltage DAC (VID0-VID4) Input High Voltage DAC (VID0-VID4) Bias Current PWM Controller Error Amplifier DC Gain Bandwidth Slew Rate CL = 10pF ---85 10 5 ---dB MHz V/µS -1.0 -2.0 20 ---28 +1.0 0.8 -36 % V V µA RT9241A RT9241B For each phase 170 85 -1.0 70 200 100 1.7 1.3 75 230 115 --80 kHz V V % 4.2 -0.2 1.19 4.35 3.85 0.6 1.25 4.6 --1.31 V V V V IDD PWM 1,2 Open -4 10 mA Symbol Test Conditions Min Typ Max Units To be continued www.richtek.com DS9241AB-01 October 2002 2 www.DataSheet4U.com RT9241A/B Parameter Current Sense GM Amplifier ISP 1,2 Full Scale Source Current ISP 1,2 Current for OCP Protection SS Current Over-Voltage Trip (VSEN/DACOUT) Power Good Upper Threshold (VSEN/DACOUT) Lower Threshold (VSEN/DACOUT) VSEN Rising VSEN Rising 106 86 110 90 114 94 % % VSS = 1V 8 118 13 122 18 126 µA % 50 70 -75 --µA µA Symbol Test Conditions Min Typ Max Units Function Block Diagram DVD VDD PGOOD VID0 VID1 VID2 VID3 VID4 Pow er On Reset Oscillator 120% VDAC DAC 108% VDAC 92% VDAC INH + _ _ + _ + + + INH OVP, PGOOD POR Logic Current Limit Current Balance Processor _ PWM Logic & Driver PWM Logic & Driver PWM1 PWMCP INH + + + _ VSEN ADJ Droop Control EA SS Control CS1 + CS2 FB GND _ COMP SS DS9241AB-01 October 2002 + _ _ _ _ + + PWM2 PWMCP ISP1 ISN1 ISP2 ISN2 www.richtek.com 3 www.DataSheet4U.com RT9241A/B Table 1 Output Voltage Program Pin Name VID4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 VID3 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 VID2 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 VID1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 VID0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 Nominal Output Voltage DACOUT Off 1.100V 1.125V 1.150V 1.175V 1.200V 1.225V 1.250V 1.275V 1.300V 1.325V 1.350V 1.375V 1.400V 1.425V 1.450V 1.475V 1.500V 1.525V 1.550V 1.575V 1.600V 1.625V 1.650V 1.675V 1.700V 1.725V 1.750V 1.775V 1.800V 1.825V 1.850V Note: (1) 0:Connected to GND (2) 1:Open www.richtek.com DS9241AB-01 October 2002 4 www.DataSheet4U.com DS9241AB-01 +5V 1µH C7 1µF 1 VID4 VDD PGOOD PHASE 17 3 PWM GND 4 ISP1 2.4K 12 2.4K Typical 12V 6 7 VCC PVCC C13 1µF 3 15 2.4K 9 DVD 2.4K ISN2 11 R13 R2 R10 C8 1µF C9 1000µF 18 R1 LGATE 5 Q2 PHB95N03LT 19 PGOOD 8 C4 1µF VID3 VID2 2 3 4 VID1 VID0 COMP FB ADJ ISN1 PWM1 5 6 7 8 13 GND 14 VSEN ISP2 20 Typical 12V R3 10K 6 7 VCC PVCC 2 BOOT 1 UGATE C3 1µF Q1 PHB83N03LT L2 2µH 0.01µF C5 1500µF C6 1500µF VCORE C1 1µF C2 1000µF/16V 12V L1 Typical Application Circuit October 2002 RT9600 2 BOOT 1 UGATE PHASE 8 C11 1µF Q3 PHB83N03LT L3 2µH 10 SS PWM2 16 VID4 +5V VID3 R15 VID2 R5 C10 6.6nF R 6 VID1 2.4K R7 24K VID0 C12 C14 R8 33pF R9 1K 12V R12 13K R14 2.4K RT9600 PWM GND 4 LGATE C17 0.1µF 5 Q4 PHB95N03LT 0.01µF C15 1500µF C16 1500µF RT9241A www.richtek.com RT9241A/B 5 www.DataSheet4U.com 6 +5V 1µF 12V 1.2µH 1000µF 1µF 12 PHB83N03LT 13 2µH 3K 12 3K 14 13 PHB95N03LT 9 UGATE2 GND ISP2 3K 11 3K 16 2µH ×1500µF PHB83N03LT 0.01µF 1µF 15 1000µF 1µF 8 PHASE2 7 LGATE 2 BOOT2 10 PGND ×1500µF 0.01µF 4 LGATE 1 PWM2 PHASE1 PWM1 UGATE1 PVCC BOOT1 VCC 5 PGOOD 1µF 11 14 10K VDD PGOOD PWM1 ISP1 ISN1 VSEN GND 18 17 19 20 10 1µF 12V 1 www.richtek.com RT9241A/B VID4 1 VID4 +5V VID3 2 VID3 VID2 3 6.6nF VID2 VID1 4 VID1 2.4K 24K VID0 5 VID0 RT9602 2 6 33pF COMP 7 FB 8 ADJ 2.4K 3 6 12V ISN2 PWM2 9 13K DVD 10 2.4K SS 0.1µF RT9241A DS9241AB-01 PHB95N03LT VCORE October 2002 www.DataSheet4U.com RT9241A/B Typical Operating Characteristics Over Current Protection at Power-Up PWM1 PWM2 PWM1 PWM2 Over Current Protection at Steady State VSS VSS IOUT 20A/DIV) Time (25mS/DIV) IOUT 20A/DIV) Time (25mS/DIV) Current Sharing between Two Phases PWM1 PWM2 Two-Phase Converter without Current Sharing PWM1 PWM2 IL1 IL2 IL1 IL2 IL1 IL2 IL1 IL2 Time (5μS/DIV) Time (5μS/DIV) 1.6 1.4 1.2 The Hysteresis of VDD 1.6 1.4 1.2 The Hysteresis of VDVD VCORE (V) VCORE (V) 1 0.8 0.6 0.4 0.2 0 1 2 3 4 5 6 1 0.8 0.6 0.4 0.2 0 0.9 1 1.1 1.2 1.3 1.4 1.5 VDD (V) VDVD (V) DS9241AB-01 October 2002 www.richtek.com 7 www.DataSheet4U.com RT9241A/B Functional Pin Description VID4, VID3, VID2, VID1 and VID0 ( Pin1,2,3,4,5) DAC voltage identification inputs for VRM9.0. These pins are TTL-compatible and internally pulled to VDD if left open. COMP (Pin 6) Output of the error amplifier and input of the PWM comparator. FB (Pin 7) Inverting input of the internal error amplifier. ADJ (Pin 8) Current sense output for active droop adjust. Connect a resistor from this pin to GND to set the amount of load droop. This pin should not be opened. DVD (Pin 9) Programmable power UVLO detection input. Trip threshold = 1.25V at VDVD rising SS (Pin 10) Connect this SS pin to GND with a capacitor to set the start time interval. Pull this pin below 1V(ramp valley of saw-tooth wave in pulse width modulator) to shutdown the converter output. ISN1 (Pin 12), ISN2 (Pin 11) Current sense inputs from the individual converter channel’s sense component GND nodes. GND (Pin 13) Ground for the IC. VSEN (Pin 14) Power good and over voltage monitor input. Connect to the microprocessor-CORE voltage. ISP1 (Pin 18), ISP2 (Pin 15) Current sense inputs for individual converter channels. Tie this pin to the component sense node. PWM1 (Pin 17), PWM2 (Pin 16) PWM outputs for each driven channel. Connect these pins to the PWM input of the MOSFET driver. PGOOD (Pin 19) Power good open-drain output. VDD (Pin 20) IC power supply. Connect this pin to a 5V supply. www.richtek.com DS9241AB-01 October 2002 8 www.DataSheet4U.com RT9241A/B Simplified Block Diagram Control Loops for a Two Phase Converter VDAC Droop ADJ Control EA _ PWM Logic & Driver PWM Logic & Driver ISP1 ISN1 ISP2 ISN2 PWM1 + + + PWMCP Current Balance PWM2 + + + _ CS1 GND SS Control COMP SS VIN CS2 RT9600 RLOAD COUT VIN RT9600 Voltage loop Current loop DS9241AB-01 October 2002 + + _ _ _ FB _ Processor PWMCP + www.richtek.com 9 www.DataSheet4U.com RT9241A/B Operation RT9241A/B is a two-phase DC/DC controller that precisely regulates CPU core voltage and balances the current of different power channels. The converter consists of RT9241A/B and its companion MOSFET driver provide high quality CPU power and all protection function to meet the requirement of modern VRM. Voltage control The reference of VCORE is provided by a 5-bit DAC of VRM9.0 specification. Control loop consists of error amplifier, two-phase pulse width modulator, driver and power components. Like conventional voltage mode PWM controller, the output voltage is locked at the VREF of error amplifier and the error signal is used as the control signal VC of pulse width modulator. The PWM signals of different channels are generated by comparison of EA output and split-phase saw-tooth