ltc1760 Linear Technology Corporation, ltc1760 Datasheet
ltc1760
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ltc1760 Summary of contents
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... A proprietary PowerPath neous charging or discharging of both batteries. Typical battery run times are extended 10%, while charging times are reduced 50%. The LTC1760 automatically switches between power sources in less than 10µs to prevent power interruption upon battery or wall adapter removal. ...
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... Ramping Down, Measured GND PLUS PLUS I = 0mA to 10mA VCC With Respect to Voltage Reported by Battery V < Requested Voltage < V CHMIN LIMIT U W ORDER PART TOP VIEW NUMBER 48 SCH2 47 GCH2 46 GCH1 LTC1760CFW 45 SCH1 44 TGATE 43 BOOST DCIN BGATE 38 PGND 37 COMP1 36 CLP 35 ...
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... I to GND) ILIMIT LIMIT R = 10k ±1% ILIMIT R = 33k ±1% ILIMIT R = Open (or Short ILIMIT LIMIT CC2 Guaranteed Monotonic (5V < V < 25V) BAT LTC1760 = 12V 3.3V 5.2V VDDS VCC2 MIN TYP MAX UNITS ● – ● – ● –8 ...
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... LTC1760 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T unless otherwise noted. SYMBOL PARAMETER V V Granularity STEP DAC V Charging Voltage Limit LIMIT (Note 7) Charge Mux Switches t GCH1/GCH2 Turn-On Time ONC t GCH1/GCH2 Turn-Off Time OFFC V CH Gate Clamp Voltage CON GCH1 GCH2 ...
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... SCL1/SDA1/SCL2/SDA2 Series Impedance to Host SMBus SCL/SDA Output Low Voltage (V LTC1760 Driving the Pin SCL1/SDA1/SCL2/SDA2 Pullup Output Low Voltage (VOL). LTC1760 Driving the Pin with Battery SMBus not Connected to Host SMBus SCL1/SDA1/SCL2/SDA2 Output Low Voltage ( LTC1760 Driving the Pin with Battery ...
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... LOAD ) ) ) Note 6. The LTC1760C is guaranteed to meet specified performance from 0°C to 70°C and is designed, characterized and expected to meet specified performance at –40°C and 85°C, but is not tested at these extended temperature limits. Note 7. Charger servos to the value reported by a Voltage() query. This is the internal cell voltage measured by the battery electronics and may be lower than the terminal voltage. See “ ...
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... TIME (MINUTES) 1760 G04 BATTERY TYPE: 10.8V Li-Ion (MOLTECH NI2020) LOAD CURRENT = 3A LTC1760 may not servo correctly SENSE will be between 4mV/R and (Requested Current – 8mA). SENSE . SENSE Dual Battery Charge Time vs Sequential Battery Charging 3500 ...
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... This pin should be connected directly to the “bottom” (output side) of the low valued resistor in series with the three PowerPath switch pairs, for detecting short-circuit current events. Also powers the LTC1760 internal circuitry when all other sources are absent. SCP (Pin 5): PowerPath Current Sensing Positive Input. ...
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... VLIMIT BAT1 (Pin 3), BAT2 (Pin 2): These two pins are the inputs from the two batteries for power to the LTC1760. LOPWR (Pin 12): LOPWR Comparator Input from Exter- nal Resistor Divider Connected from SCN to GND. If the voltage at LOPWR pin is lower than the LOPWR com- ...
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... PULLUP 10 SDA2 (Pin 21): SMBus Data Signal to Smart Battery 2. Do not connect to an external pull-up. The LTC1760 connects this pin to an internal pull-up (I SDA (Pin 22): SMBus Data Signal to SMBus Host. Also used to indicate charging status of Battery 2. Requires an ...
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... SWB2 SWDC DRIVER DRIVER DRIVER SEQUENCER AC_PRESENT CHARGE PowerPath CONTROLLER 0.86V – 0V CSN + – Ω 1. 0. LTC1760 100mV 5 SCP + SHORT CIRCUIT 100Ω – SCN LIMIT DECODER CC2 10µA SMBALERT 29 MODE SCL 18 22 SDA SMBus ...
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... Voltage() ('h09) ........................................................................................................................................................................... 19 2.3.7 Current() ('h0a) ............................................................................................................................................................................ 20 2.3.8 ChargingCurrent() ('h14) ............................................................................................................................................................. 20 2.3.9 ChargingVoltage() ('h15) ............................................................................................................................................................. 20 2.3.10 AlarmWarning() ('h16) ................................................................................................................................................................ 20 2.3.11 AlertResponse() ........................................................................................................................................................................... 21 2.4 SMBus Dual Port Operation ............................................................................................................................................................. 21 2.5 LTC1760 SMBus Controller Operation ............................................................................................................................................. 22 2.6 LTC1760 SMBALERT Operation ...................................................................................................................................................... 24 3 Charging Algorithm Overview .............................................................................................................................................................. 24 3.1 Wake-Up Charging Initiation ............................................................................................................................................................ 24 3.2 Wake-Up Charging Termination ....................................................................................................................................................... 24 3.3 Wake-Up Charging Current and Voltage Limits ............................................................................................................................... 25 3.4 Controlled Charging Initiation .......................................................................................................................................................... 25 3.5 Controlled Charging Termination ...
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... SMBus Host. The SMBus Interface supports true dual port operation by allowing the SMBus Host to be connected to the SMBus of either battery. The LTC1760 is able to operate as an SMBus master or slave device. References: Smart Battery System Manager Specification: Revision 1 ...
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... LTC1760 U OPERATIO 2.2 Data Bit Definition of Supported SMBus Functions. LTC1760 SMBus Function Mode Access BatterySystemState() Slave Read/ Write BatterySystemStateCont() Slave Read/ Write BatterySystemInfo() Slave Read LTC() Slave Read/ Write BatteryMode() Master Read 14 SMBus Command Data Address Code Type D15 D14 D13 D12 D11 D10 D09 D08 D07 D06 D05 D04 D03 D02 D01 D00 ...
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... AlarmWarning () Master Read AlertResponse () Slave Read see (1) Byte (1) Read-byte format. 'h14 is returned as the interrupt address of the LTC1760. SMBus Command Data Address Code Type D15 D14 D13 D12 D11 D10 D09 D08 D07 D06 D05 D04 D03 D02 D01 D00 7'b0001_011 8'h0a ...
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... A and B to simultaneously communicate with the system host, the LTC1760 will just ignore the request. 2.3.1 BatterySystemState() ('h01) Description: This function returns the present state of the LTC1760 and allows access to individual batteries. The information is broken into four nibbles that report: Which battery is communicating with the SMBus Host ...
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... DCDIV pin to measure the presence of AC. Allowed values are: 'b1: The LTC1760 has determined that AC is present. 'b0: The LTC1760 has determined that AC is not present. POWER_NOT_GOOD Bit The read only POWER_NOT_GOOD bit is used to show that the voltage delivered to the system load is inadequate. ...
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... Writing this bit has no effect. A read of this bit always returns a 0. CALIBRATE Bit The read/write CALIBRATE bit is used either to show the status of battery calibration cycles in the LTC1760 or to begin or end a calibration cycle. 18 CALIBRATE_BAT[4:1] Nibble The read/write CALIBRATE_BAT[4:1] nibble is used by the SMBus Host to select the battery to be calibrated or to determine which individual battery is being calibrated ...
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... Battery requires calibration. (Also known as a Condition Cycle Request). 'b0 - Battery does not require calibration. 2.3.6 Voltage() ('h09) Description: This function is used by the LTC1760 to read the actual cell-pack voltage . Purpose: Allows the LTC1760 to determine the cell pack voltage and close the charging voltage servo loop. ...
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... Output: unsigned integer — maximum charger output current in mA. Refer to "Section 2.2" for bit mapping. Units: mA. Range 65,534 mA. 2.3.9 ChargingVoltage() ('h15) Description: This function is used by the LTC1760 to read the Smart Battery’s desired charging voltage. 20 Purpose: Allows the LTC1760 to determine the maximum charging voltage. ...
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... SMBus Protocol: A 7-bit Addressable Device Responds to an ARA. Output: The device address will be sent to the SMBus Host. The LTC1760 device address is 0x14 (or 0x0a if just looking at the 7 bit address field). The following events will cause the LTC1760 to pull-down the SMBALERT# bus through the SMBALERT pin: • ...
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... BAT1 ORIGINATED COMMANDS ARE IGNORED. (1c) *SMB INCLUDES SCL AND SDA, SMB1 INCLUDES SCL1 AND SDA1, AND SMB2 INCLUDES SCL2 AND SDA2. Figure 1. Switch Configurations Used by the LTC1760 for Managing Dual Port Battery Communication 2.5 LTC1760 SMBus Controller Operation SMBus communication with the LTC1760 is handled by the SMBus Controller, a sub-block of the SMBus Interface ...
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... U OPERATIO LTC1760 1760f 23 ...
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... LTC1760 U OPERATIO 2.6 LTC1760 SMBALERT Operation The SMBALERT pin allows the LTC1760 to signal to the SMBus Host that there has been a change of status. This pin is asserted low whenever there is a change in battery presence, AC presence or after a power on reset event. This pin is cleared during an Alert Response or ...
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... The battery responds to an LTC1760 master read of ChargingVoltage() with a non zero voltage request value. 7. The battery responds to an LTC1760 master read of Voltage(). 8. The battery responds to an LTC1760 master read of ChargingCurrent() with a non zero current request value. 9. The battery responds to an LTC1760 master read of Current(). ...
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... LTC(TURBO) provides a mechanism for the SMBus Host to put additional current into both batteries. Normally the LTC1760 will limit the current into both batteries to the maximum of the two requested currents + I LTC(TURBO) is asserted, this restriction is removed, allowing the charger to output as much as I batteries ...
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... System Power Management Algorithm and Battery Calibration 4.1 Turning Off System Power The LTC1760 allows the user to turn off system power using the LTC(POWER_OFF) bit. When POWER_OFF is asserted high all power management functions are by- passed and the LTC1760 will turn off DCIN, BAT2 and BAT1 power paths ...
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... BatterySystemStateCont(POWER_NOT_GOOD) is high. • The battery sets Alarm Warning (TERMINATE_DISCHARGE) high. • The battery sets Alarm Warning (FULLY_DISCHARGED) high. • A zero is written to the CALIBRATE bit. The LTC1760 will attempt to initiate a charge cycle after the discharge cycle is completed. 1760f ...
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... Charging When SCL And SDA Are Low When MODE is tied to V SCL are not used and will not interfere with LTC1760 battery communication. This feature allows the LTC1760 to autonomously charge when SCL and SDA are not available. This scenario might occur when SMBus Host has powered down and is no longer pulling up on SCL and SDA ...
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... LTC1760 U OPERATIO OFF TGATE ON t OFF ON BGATE OFF INDUCTOR CURRENT Figure 4. at hand. The average current control loop converts the voltage between CSP and BAT to a representative current. Error amp CA2 compares this current against the desired current programmed by the I at the I ...
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... The charger will stop within a few microseconds, leaving a small current which must be provided by the capacitor LOAD 1760 F06 PLUS LTC1760 to fall below the UVLO threshold. If the PLUS must be large enough to keep the circuit PLUS . The recommended minimum values (1µF on TSC 1760f 31 ...
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... V , including tolerances) should keep PLUS CC the LTC1760 operating above the UVLO trip voltage long enough to perform the short-circuit function when the input voltages are greater than 8V. Increasing the capaci- tor across V to 4.7µF will allow operation down to the CC recommended 6V minimum ...
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... Capacity rating will change with age and use and hence the current sharing ratios can change over time. Adapter Limiting An important feature of the LTC1760 is the ability to automatically adjust charging current to a level which avoids overloading the wall adapter. This allows the prod- uct to operate at the same time that batteries are being charged without complex load management algorithms ...
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... Consult the battery manufacturer for information on how your battery terminates charging. Setting Charger Output Current Limit The LTC1760 current DAC and the PWM analog circuitry must coordinate the setting of the charger current. Failure will result in incorrect charge currents. ...
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... The constant k = 1.7 can be used to estimate the contribu- tions of the two terms in the main switch dissipation equation. If the LTC1760 charger is to operate in low dropout mode or with a high duty cycle greater than 85%, then the topside N-channel efficiency generally improves with a larger MOSFET. Using asymmetrical MOSFETs may achieve cost savings or efficiency gains ...
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... LTC1760 U U APPLICATIO S I FOR ATIO For thermistors that are IDEAL-RANGE 4/64 • V /(RXB + R SAFETYX VCC2 (R1A +R ) THX For thermistors that are HOT-RANGE 4/64 • V /(RXB + R SAFETYX VCC2 (R1A +R ) THX R is the impedance of the battery’s thermistor to THX ground. RXB = 54.9k RXA = 1.13k Sample calculation of I ...
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... U U APPLICATIO S I FOR ATIO Calculating IC Power Dissipation The power dissipation of the LTC1760 is dependent upon the gate charge of Q and Application). The gate charge is determined from the manufacturer’s data sheet and is dependent upon both the gate voltage swing and the drain voltage swing of the FET. ...
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... DS(ON) R value becomes unreasonably low for MOSFETs DS(ON) available at this time. The need for the LTC1760 voltage drop regulation only comes into play for parallel battery configurations that terminate charge or discharge using voltage. At first this seems problem, but there are several factors helping out: 1 ...
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... GATE DRIVE I is the fixed drive current into the gate from the DRIVE LTC1760 and “t” is the time it takes to move that charge to a new state and change the MOSFET conduction mode. Hence time is directly related to Q GATE up with MOSFETs of lower R ...
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... LTC1760 U U APPLICATIO S I FOR ATIO A) Single Battery Configuration. To limit the LTC1760 to a single battery, modify the battery slot to be eliminated as follows: 1) Remove both FETs (Q5 Q7, Q8) involved in the charge path. 2) Remove both FETS (Q3 Q9, Q10) involved in the discharge path. ...
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... Although every effort is made to meet and exceed all required “SMBus Charger V1.1” safety features it is the responsibility of the battery pack to protect itself from excessive currents or voltages. The LTC1760 is not itself a safety device. Consult your battery pack manufacturer for more information. LTC1760 to CSP and BAT ...
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... C1 0.1µF I6 CB2 0.47µF D1: MBR130T3 D2: IN4148 TYPE Q1, Q2, Q5, Q6, Q7, Q8: Si4925DY Q3, Q4, Q9, Q10, QTG, QBG: FDS6912A 42 Application for a Dual Battery System (12.6V/4A) PowerPath MUX C8, 1µF R10, 100Ω Q1 C9, 0.1µF LTC1760 CLP PLUS 7 DC GDCI GDCO BAT1 2 9 BAT2 ...
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... BSC LTC1760 (.311 – .327) 1.10 (.0433) MAX 0.17 – 0.27 0.05 – 0.15 (.002 – .006) TYP 7.9 – 8.3 -T- ...
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