LTC3789 LINER [Linear Technology], LTC3789 Datasheet
LTC3789
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LTC3789 Summary of contents
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FeaTures Complete High Performance Battery Charger When n Paired with a DC/DC Converter Wide Input and Output Voltage Range 60V n Input Ideal Diode for Low Loss Reverse Blocking n and Load Sharing Output Ideal Diode for Low ...
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LTC4000 absoluTe MaxiMuM raTings (Note 1) IN, CLN, IID, CSP, CSN, BAT ....................... –0.3V to 62V IN-CLN, CSP-CSN ............................................– OFB, BFB, FBG ........................................... –0.3V to 62V FBG ............................................................–1mA to 2mA IGATE ...........Max ( – 10V ...
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T SYMBOL PARAMETER V Input Supply Operating Range IN I Input Quiescent Operating Current IN I Battery Pin Operating Current BAT Battery Only Quiescent Current Shutdown ENC Input Voltage Low ENC ...
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LTC4000 elecTrical characTerisTics junction temperature range, otherwise specifications are at T SYMBOL PARAMETER Charge Termination CX Pin Pull-Up Current V CX Comparator Offset Voltage, IBMON Falling CX,IBMON(OS Comparator Hysteresis Voltage CX,IBMON(HYS) TMR Pull-Up Current TMR Pull-Down Current TMR ...
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T SYMBOL PARAMETER Battery PowerPath Control Battery Discharge PowerPath Forward Regulation Voltage Battery PowerPath Fast Reverse Turn-Off Threshold Voltage Battery PowerPath Fast Forward Turn-On Threshold Voltage Battery Gate Turn-Off Current Battery ...
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LTC4000 Typical perForMance characTerisTics Input Quiescent Current and Battery Quiescent Current Over Temperature 1 15V IN BAT V = 15.5V CSN I IN 0.1 I BAT 0 –60 –40 – 100 ...
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Typical perForMance characTerisTics Charge Termination Time with 0.1µF Timer Capacitor Over Temperature 3.5 3.3 3.1 2.9 2.7 2.5 2.3 –60 –40 – 100 120 TEMPERATURE (°C) 4000 G10 PowerPath Fast Off, Fast On and Forward ...
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LTC4000 pin FuncTions (QFN/SSOP) VM (Pin 1/Pin 25): Voltage Monitor Input. High impedance input to an accurate comparator with a 1.193V threshold (typical). This pin controls the state of the RST output pin. Connect a resistor divider (R VM1 monitored ...
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FuncTions (QFN/SSOP) CL (Pin 8/Pin 4): Charge Current Limit Programming. Con- nect the charge current programming resistor (R pin. This pin sources 50µA of current. The regulation loop compares the voltage on this pin with the charge current monitor ...
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LTC4000 pin FuncTions (QFN/SSOP) BGATE (Pin 18/Pin 14): External Battery PMOS Gate Drive Output. When not charging, the BGATE pin drives the external PMOS to behave as an ideal diode from the BAT pin (anode) to the CSN pin (cathode). ...
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FuncTions (QFN/SSOP) CC (Pin 25/Pin 21): Converter Compensation Pin. Connect an R-C network from this pin to the ITH pin to provide a suitable loop compensation for the converter used. Refer to the Applications Information section for discussion and ...
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LTC4000 block DiagraM CLN CLN R VM1 VM CP1 – R VM2 + 1.193V 0.33m m IIMON 60k BIAS 50µ LDO, BG, REF REF C BIAS ...
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Overview The LTC4000 is designed to simplify the conversion of any externally compensated DC/DC converter into a high performance battery charger with PowerPath control. It only requires the DC/DC converter to have a control or external-compensation pin (usually named ...
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LTC4000 operaTion The ideal diode behavior is achieved by controlling an external PMOS connected to the IID pin (drain) and the CSP pin (source). The controller (A1) regulates the external PMOS by driving the gate of the PMOS device such ...
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Charge Current Regulation The first loop involved in a normal charging cycle is the charge current regulation loop (Figure 3). As with the input current regulation loop, this loop also drives the ITH and CC pins. This loop ensures ...
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LTC4000 operaTion to be approximately 86% of the final float voltage level (V ). This feature provides a CSP voltage sig- OUT(INST_ON) nificantly higher than the battery voltage when charging into a heavily discharged battery. This instant-on feature allows the ...
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Input Ideal Diode PMOS Selection The input external PMOS is selected based on the expected maximum current, power dissipation and reverse volt- age drop. The PMOS must be able to withstand a gate to source voltage greater than ...
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LTC4000 applicaTions inForMaTion Charge Current Limit Setting and Monitoring The regulated full charge current is set according to the following formula • I CLIM where V is the voltage on the CL pin. The ...
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TMR pin, a bad battery detection timer is started as soon as trickle charging starts the end of the bad battery detection time the battery voltage is still lower than the low battery threshold, charging is ...
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LTC4000 applicaTions inForMaTion Battery Instant-On and Ideal Diode External PMOS Consideration The instant-on voltage level is determined using the fol- lowing formula OFB1 OFB2 V = OUT(INST _ ON) R OFB2 Note that R and R are ...
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Similar to the input external PMOS, the charging external PMOS must be able to withstand a gate to source voltage greater than V (15V maximum) or the maximum BGATE(ON) regulated voltage at the CSP pin, whichever is less. ...
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... NTC pin NTC and the GND pin, and a bias resistor, R3, from the BIAS pin to the NTC pin (Figure 9). Thermistor manufacturer datasheets usually include either a temperature lookup table or a formula relating temperature to the resistor value at that corresponding temperature. BIAS LTC4000 ...
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The value of R3 and R can now be set according to the D following formula cold_ threshold – R NTC NTC R3 = 2.461 R = 0.219 • cold_ threshold – D NTC ...
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LTC4000 applicaTions inForMaTion Setting the Input Voltage Monitoring Resistor Divider The falling threshold voltage level for this monitoring function can be calculated as follows: V ⎛ ⎞ RST R – 1 ⎟ • ⎜ VM1 VM2 ...
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SWITCHING CONVERTER GND ITH ITH CLN LTC4000 IN GND BAT V IN Generator frequency is set at 50Hz. Lower frequencies may cause a blinking scope display and higher frequen- cies may not allow sufficient settling time for the ...
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LTC4000 applicaTions inForMaTion Figure 13. Typical Output Transient Response at Various Stability Level If the regulator response is under damped with the initial large value should be increased immediately before C C larger values of C ...
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DESIGN EXAMPLE In this design example, the LTC4000 is paired with the LT3845 buck converter to create a 10A, 3-cell LiFePO battery charger. The circuit is shown on the front page and is repeated here in Figure 14. ...
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LTC4000 applicaTions inForMaTion • The charge termination time is set at 2.9 hours accord- ing to the following formula: C (nF (h) • 34.6 = 2.9 • 34.6 = 100nF TMR TERMINATE • The C/X current termination level ...
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With C = 1µ 10k 20V regulated at 9.8V and a 0.2A output load condition at CSP , the transient response for a 100mA charge current step observed ...
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LTC4000 applicaTions inForMaTion This same procedure is then repeated for the other four loops: the input current regulation, the output voltage regulation, the battery float voltage regulation and finally the charge current regulation when V Note that the resulting optimum ...
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APPENDIX—THE LOOP TRANSFER FUNCTIONS When a series resistor (R ) and capacitor ( the compensation network as shown in Figure 11, the transfer function from the input of A4-A7 to the ITH pin is simply as ...
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LTC4000 applicaTions inForMaTion The Output Voltage Regulation Loop The feedback signal for the output voltage regulation loop is the voltage on the OFB pin, which is connected to the center node of the resistor divider between the output voltage (connected ...
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In Figure 22 the battery is approximated signal ground in series with the internal battery resistance R Therefore, the simplified loop transmission is as follows: ⎡ ⎛ ⎞ – ⎟ ...
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LTC4000 applicaTions inForMaTion The Battery Charge Current Regulation Loop when V is Regulated to V OFB OUT(INST_ON) When the battery voltage is below the instant-on level, the external charging PFET is driven linearly to regulate the voltage at the output ...
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Typical applicaTions 15V TO 60V 2.2µF 10A MAX 47µ 1.5nF BURST_EN SYNC SGND LT3845A f SET 49.9k SHDN RST CLN IN 1µF 1.10M VM 100k ENC BZX84C3VO CHRG FLT IIMON 10nF IBMON 10nF Figure 25. ...
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LTC4000 Typical applicaTions V 3.3mΩ 2.5mΩ 18V 15A MAX 150µF 22µF ×4 INTV CC 100k 4.7µF 0.1µF RST CLN IN 1µF 383k VM 100k ENC CHRG FLT IIMON 10nF IBMON 10nF Figure 26 21V at ...
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Typical applicaTions LTC4000 4000f 37 ...
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LTC4000 package DescripTion 4.50 ± 0.05 3.10 ± 0.05 2.50 REF 2.65 ± 0.05 0.25 ±0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED PIN 1 TOP MARK (NOTE 6) 5.00 ...
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DescripTion .254 MIN .0165 ± .0015 RECOMMENDED SOLDER PAD LAYOUT .0075 – .0098 (0.19 – 0.25) .016 – .050 (0.406 – 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) 3. DRAWING NOT TO SCALE *DIMENSION ...
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... B240A B240A 0.22µF 0.01 1.24k 1.24k + – SW1 BG1 SENSE SENSE BG2 SW2 TG2 BOOST2 DFLS160 INTV CC MODE/PLLIN 100k LTC3789 PGOOD + I OSENSE – I OSENSE V OUTSNS BZT52C5V6 EXTV CC 154k V FB ITH SS SGND PGND1 8.06k 0.01µF 14.7k 100nF ITH CC LTC4000 IL CL ...