L6711TR STMicroelectronics, L6711TR Datasheet
L6711TR
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L6711TR
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L6711TR Summary of contents
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... High current VRM/VRD for desktop / Server / Workstation CPUs High density DC/DC Converters Order codes Part Number L6711 L6711TR April 2006 TQFP48 (Exposed Pad) Description The device implements a three phase step-down controller with a 120° phase-shift between each phase with integrated high current drivers in a compact 7x7mm body package with exposed pad ...
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Contents Contents 1 Typical application circuit and block diagram . . . . . . . . . . . . . . . . . . . . 4 1.1 Application circuit . . . . . . . ...
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L6711 12 Enable and disable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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Typical application circuit and block diagram 1 Typical application circuit and block diagram 1.1 Application circuit Figure 1. Typical application circuit for LS MOSFET current sense V IN GND IN VID5 VID4 VID3 VID2 VID1 VID0 VID_SEL OUTEN C F ...
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L6711 Figure 2. Typical application circuit for inductor DCR current sense V IN GND IN VID5 VID4 VID3 VID2 VID1 VID0 VID_SEL OUTEN L6711 REF. SCH. (INDUCTOR) Typical application circuit and block diagram L ...
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Typical application circuit and block diagram 1.2 Block diagram Figure 3. Block diagram OUTEN OUTEN OSC TC DIGITAL SOFT START VID0 VID1 VID2 VID3 VID4 VID5 VID_SEL 1.240V 6/50 HS1 HS1 HS2 LS2 LOGIC PWM LOGIC PWM ADAPTIVE ANTI ADAPTIVE ...
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L6711 2 Pins description and connection diagrams Figure 4. Pins connection (top view) N.C. VCCDR3 PGND2 LGATE2 VCCDR2 PHASE2 UGATE2 BOOT2 BOOT1 UGATE1 PHASE1 N.C. 2.1 Pin descriptions Table 1. Pins description N° Name Channel 1 LS driver supply: it ...
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Pins description and connection diagrams Table 1. Pins description N° Name This pin is connected to the error amplifier inverting input and is used to compensate the voltage control feedback loop Connecting a resistor between this pin and ...
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L6711 Table 1. Pins description N° Name Channel 2 Current Sense Positive Input pin. It must be connected through an Rg resistor to the LS mosfet source (or to the GND-side of the sense resistor placed in series to the ...
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Pins description and connection diagrams Table 1. Pins description N° Name Voltage IDentification pins. Internally pulled-up to 3V, connect to SGND to program a logic ‘0’ while leave floating (as well VID5, as pull-up with a resistor up to 3.3V) ...
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L6711 Table 1. Pins description N° Name Channel 1 HS driver supply. This pin supplies the relative high side driver. 45 BOOT1 Connect through a capacitor (100nF Typ.) to the PHASE1 pin and through a diode to VCC (cathode vs. ...
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Maximum ratings 3 Maximum ratings 3.1 Absolute maximum ratings Table 2. Absolute maximum ratings Symbol V , VCCDRx To PGNDx BOOTx Boot Voltage V PHASEx V - UGATEx V PHASEx LGATEx, PHASEx to PGNDx VID0 to VID5 ...
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L6711 4 Electrical specifications Table 4. Electrical characteristcs (V CC Symbol V supply current CC I VCC supply current CC VCCDRx supply I CCDRx current I BOOTx supply current BOOTx Power-ON Turn-On VCC threshold Turn-Off VCC threshold Turn-On VCCDRx Threshold ...
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Electrical specifications Table 4. Electrical characteristcs (continued Symbol Reference and DAC Output Voltage Accuracy VID, VID_SEL I , VID I pull-up Current VID_SEL VID, VID_SEL pull-up Voltage VID, VID_SEL VID IL Threshold VID IH Error amplifier A DC ...
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L6711 Table 4. Electrical characteristcs (continued Symbol Thermal sensor TC Voltage 27ºC amb Gate drivers High Side t RISE HGATE Rise Time High Side I HGATEx Source Current High Side R HGATEx Sink ...
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VID Tables 5 VID Tables Table 5. Voltage IDentification (VID) Codes. VID5 VID4 VID3 VID2 VID1 VID0 ...
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L6711 Table 6. Voltage IDentification (VID) Codes. HAMMER DAC VID5 VID4 VID3 VID2 VID1 VID0 ...
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Device description 6 Device description The device is a three phase PWM controller with embedded high current drivers that provides complete control logic and protections for a high performance step-down DC-DC voltage regulator optimized for advanced microprocessor power supply. Multi ...
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L6711 7 Current reading and current sharing control loop The device embeds a flexible, fully-differential current sense circuitry that is able to read across both low side or inductor parasitic resistance or across a sense resistor placed in series to ...
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Current reading and current sharing control loop 50 A offset allows negative current reading, enabling the device to check for dangerous returning current between the phases assuring the complete current equalization. From the current information of each phase, information about ...
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L6711 current information of each phase, information about the total current delivered ( INFO1 INFO2 INFO3 I )/3) is taken. I INFO3 in order to equalize the current carried by the three phases. Since Rg is ...
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DAC Selection 8 DAC Selection The device embeds a selectable DAC that allows the output voltage to have a tolerance of ±0.5% (0.6% for Hammer DAC) recovering from offsets and manufacturing variations. The VID_SEL pin selects the DAC table used ...
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L6711 9 Remote voltage sense The device embeds a Remote Sense Buffer to sense remotely the regulated voltage without any additional external components. In this way, the output voltage programmed is regulated between the remote buffer inputs compensating motherboard or ...
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Voltage positioning 10 Voltage positioning Output voltage positioning is performed by selecting the reference DAC and by programming the different contributors to the I sourced from the FB pin, causes the output voltage to vary according to the external R ...
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L6711 Since I depends on the current information about the three phases, the output DROOP characteristic vs. load current is given by: VID R – OOP Where R is the chosen sensing element resistance (Inductor DCR or ...
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Voltage positioning Offset resistor can be designed by considering the following relationship (R Droop effect): 1.240V R = ------------------ - R OFFSET V OS Offset automatically given by the DAC selection or by VID5 when VID_SEL=SGND differs from the offset ...
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L6711 The ITS circuit subtracts from the I temperature as follow (see considered): V T,I VID R = OUT OUT where ---------- - where A and B are positive constants depending on the value ...
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Dynamic VID transitions 11 Dynamic VID transitions The device is able to manage Dynamic VID Code changes that allow Output Voltage modification during normal device operation. OVP and UVP signals are masked during every VID transition and they are re-activated ...
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L6711 11.1 VID_SEL = OPEN. Selecting the VRD10.x DAC, the device checks for VID code modifications on the rising edge of a clock that is three times the switching frequency of each phase and waits for a confirmation on the ...
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Dynamic VID transitions 11.2 VID_SEL = GND. Selecting the HAMMER DAC, the device checks for VID code modifications on the rising edge of a clock that is the same frequency of each phase and waits for a confirmation on the ...
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L6711 12 Enable and disable The device has three different supplies: VCC pin to supply the internal control logic, VCCDRx to supply the low side drivers and BOOTx to supply the high side drivers. If the voltage at pins VCC ...
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Soft start 13 Soft start During soft start, a ramp is generated increasing the loop reference from 0V to the final value programmed by VID in 2048 clock periods as shown in Figure 15. Once the soft start begins, the ...
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L6711 14 Output voltage monitor and protections The device monitors through pin VSEN the regulated voltage in order to manage the OVP / UVP conditions. 14.1 UVP protection If the output voltage monitored by VSEN drops below the 60% of ...
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Output voltage monitor and protections Figure 16. Output voltage protections and typical principle connections to assure complete protection Vcc TurnON PreOVP TurnON 14.4 Over current Depending on the current reading method selected, the device limits the peak or ...
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L6711 14.5 Low side sense overcurrent (CS_SEL=OPEN) The device detects an Over Current condition for each phase when the current information I overcomes the fixed threshold of I INFOx keeps the relative LS mosfet on, skipping clock cycles, until the ...
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Output voltage monitor and protections 14.5.2 Constant current operation This happens when the on-time limitation is reached after the valley current in each phase reaches I (I OCPx INFOx The device enters in Quasi-Constant-Current operation: the low-side mosfets stays ON ...
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L6711 Figure 18. Constant current operation Maximum current for each phase 14.6 Inductor sense over current (CS_SEL = SGND) The device detects an over current when the I Since the device always senses ...
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Oscillator 15 Oscillator The internal oscillator generates the triangular waveform for the PWM charging and discharging with a constant current an internal capacitor. The switching frequency for each channel internally fixed at 150kHz so that the resulting ...
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L6711 16 Driver section The integrated high-current drivers allow using different types of power MOS (also multiple MOS to reduce the equivalent R The drivers for the high-side mosfets use BOOTx pins for supply and PHASEx pins for return. The ...
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Driver section Moreover, since the device has an exposed pad to better dissipate the power, also the thermal resistance between junction and ambient is important. Figure 16 shows the Switching Power for different kind of mosfets driven. Figure 20. Controller ...
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L6711 17 System control loop compensation The control loop is composed by the Current Sharing control loop and the Average Current Mode control loop. Each loop gives, with a proper gain, the correction to the PWM in order to minimize ...
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System control loop compensation V 4 PWM = -- - --------------- 5 V amplitude and has a typical value of 3V Removing the dependence from the Error Amplifier gain, so assuming this gain high enough, the control loop gain results: ...
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L6711 Figure 22. Equivalent Control Loop Gain Block Diagram (left) and Bode Diagram (right ...
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Layout guidelines 18 Layout guidelines Since the device manages control functions and high-current drivers, layout is one of the most important things to consider when designing such high current applications. A good layout solution can generate a benefit in lowering ...
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L6711 18.2 Power connections related. Figure 24 shows some small signal components placement. Gate and phase traces must be sized according to the driver RMS current delivered to the power mosfet. The device robustness allows managing applications with the power ...
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Layout guidelines 18.3 Current sense connections. Remote Buffer: The input connections for this component must be routed as parallel nets from the FBG/FBR pins to the load in order to compensate losses along the output power traces and also to ...
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L6711 19 Embedding L6711-based VRDs... When embedding the VRD into the application, additional care must be taken since the whole VRD is a switching DC/DC regulator and the most common system in which it has to work is a digital ...
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TQFP48 Mechanical data & package dimensions 20 TQFP48 Mechanical data & package dimensions Figure 25. TQFP48 Mechanical data & package dimensions mm DIM. MIN. TYP 0.05 A2 0.95 1.00 b 0.17 0.22 c 0.09 D 8.80 9.00 D1 ...
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L6711 21 Revision history Table 8. Revision History Date 01-Jun-2004 23-Nov-2004 26-Oct-2005 18-Apr-2006 Revision 1 First Issue 2 Modificated the Paragraph 18.2 on the page 32/38. 3 Added new paragraph 9.1.2 Warning 2. 4 Updated graphic, Modified Table1 Revision history ...
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