DS2711 MAXIM [Maxim Integrated Products], DS2711 Datasheet
DS2711
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DS2711 Summary of contents
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... DESCRIPTION The DS2711 and DS2712 are ideal for in-system or stand-alone charging AAA NiMH “loose” cells. Temperature, voltage, and charge time are monitored to provide proper fast charging control algorithms for nickel metal hydride (NiMH) batteries. Battery tests are included to detect defective or inappropriate cells such as alkaline primary batteries ...
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... DS2712 DS2712Z DS2712Z/T&R DS2712 DS2711Z+ DS2711 DS2711Z+T&R DS2711 DS2712Z+ DS2712 DS2712Z+T&R DS2712 DS2711E+ DS2711 DS2711E+T&R DS2711 DS2712E+ DS2712 DS2712E+T&R DS2712 + Denotes lead-free package. ABSOLUTE MAXIMUM RATINGS* Voltage on All Pins Relative to V Voltage on DMSEL Continuous Sink Current CC1, CC2, LED1, LED2 and CSOUT ...
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... THM-MIN (Notes (Notes Parallel: V ≥ 4.0V PTST Series: V ≥ 4. 0V, VP1 = 1.5V LKGR VP2 = 3.0V V (Note IREF G DS2711 (Note DS2712 (Note 8) M DS2712, 2mV t PDLY over/underdrive DS2712 CONDITIONS t BASE CC1 CC1 CC1, CC2 MIN TYP MAX UNITS ...
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PARAMETER SYMBOL Duty Factor, Parallel Precharge/Top-Off Duty Factor, Maintenance Charge Cell Test Interval Precharge Time-Out Fast-Charge Termination Hold-Off Period Fast-Charge Flat Voltage Time-Out Charge Timer Period Charge Timer Accuracy Charge Timer Range t CTMR-RANGE Note 1: Voltages relative to V ...
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Figure 1. BLOCK DIAGRAM ...
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Figure 2. STATE DIAGRAM VDD < VPOR -VHYS (asynchronously from anywhere) POR Standby power CCx = Hi-Z LEDx = Hi-Z t < PCTimeout PreCHG OR CCx = Active 12.5% Par., 25% Ser. VBAT < 1V LEDx = Charging VBAT > ...
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... DETAILED DESCRIPTION Charge Algorithm Overview A charge cycle begins in one of three ways: with the application of power to the DS2711 with cell(s) already inserted, with the detection of cell insertion after power-up, or when exiting suspend mode with cell(s) inserted. The charge cycle begins with precharge qualification to prevent fast charging of deeply depleted cells or charging under extreme temperature conditions ...
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Parallel Charge Configuration The parallel configuration supports two slot stand-alone chargers. Charge pulses are fed alternately to each cell under the control of the CC1 and CC2 pins so the charge regimes occur in parallel. The duty cycle on CC1 ...
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DS2712 Parallel Charge Configuration with Switch-Mode Charge Current Regulation The example in Figure 5 uses the DS2712 to regulate charge current as a switching (buck) regulator. ICHG is set to 2A using RSNS = 0.056Ω. The effective charge current for ...
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... In case the internal clock should ever fail, a watchdog detection circuit halts charging. The watchdog safety circuit and charge timer set by the TMR pin are derived from separate oscillators than the main clock source. Current-Sense Amplifier (DS2711) An error amplifier block provides several options to regulate the charge current. The 20mA open-drain output can drive a PMOS or PNP pass element for linear regulation, or the output can drive an optocoupler for isolated feedback to a primary-side PWM controller ...
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... Connecting an external 10kΩ NTC thermistor between THM1 or THM2 (THMx) and V between V and THMx allows the DS2711 to sense temperature. To sense the temperature of the battery cells, DD locate the thermistor close to the body of the battery cell so THM1 monitors the temperature of cell-1 and THM2 monitors the temperature of cell-2 ...
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... When the charge timer expires in top-off, the charger enters maintenance and delivers 1/64 of the charge source current to the cells. Maintenance charge continuous until power is removed, the cell(s) are removed or the DS2711/DS2712 is cycled into and out of suspend mode by floating the TMR pin. ...
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Table 3. CHARGE MODE SELECTION LED2 PIN STRAPPING Low Floating High CC1 and CC2 Outputs The CC1 and CC2 operate as open-drain outputs that drive active low to connect the charge source to the battery cell. During charge, the behavior ...
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Table 4. PARALLEL CONFIGURATION, EACH CELL MODE Cell Capacity 900mAH Fast C/3.72 Precharge/Top-Off C/14.4 Maintenance C/115 Series and Single Cell Charging Example: In the series and single-cell modes, the effective fast charge current is equal to 0.969 times the regulated ...
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REVISION HISTORY REVISION DATE Changed Figure 2 to include “T <0” condition to move from Pre-Charge to 120808 Fault state. DESCRIPTION PAGES CHANGED 6 ...