DS2712 Maxim Integrated Products, Inc., DS2712 Datasheet
DS2712
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DS2712 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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... 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 Operating Temperature Range ...
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... THM-MAX (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 0.2V 0.2 -1 ...
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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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... Charge TMR Timer 0.1V BIAS Watchdog Oscillator UVLO State Machine Presence Test Pre-Charge Fast Charge & Cell Tests Top-Off Charge Maintenance Charge 0.125V SUSPEND PTST PTST VP1 Voltage VP2 and VN1 Temperature THM1 Measurement THM2 + - VN0 VSS CSOUT - + DS2711 - + DS2712 ...
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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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... DS2711. Current regulation is performed outside of this example schematic using the current-sense feedback provided by the DS2711 CSOUT pin. The DS2712 can also be used in this circuit to provide switch-mode control on the CSOUT pin. RSNS = 0.125W sets the charge source current, ICHG, to 1A. In series mode, the effective charge current is 0 ...
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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 = 0.056W. The effective charge current for each cell is ICHG x 0.484 = 968mA. The CSOUT comparator output switches OFF when the voltage across the sense resistor goes above 0.125V and back ON when the voltage drops below 0 ...
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... V Current-Sense Comparator (DS2712) The comparator in the DS2712 switches between ON and OFF and is capable of driving a PNP bipolar or a PMOS transistor, enabling the use of a switched-mode power stage. Hysteresis on the comparator input provides noise rejection. In the closed-loop regulation circuit of Figure 5, the comparator regulates voltage across the sense ...
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Charge Timer The charge timer monitors the duration of charge in fast and top-off charge phases, and is reset at the beginning of each phase. The time-out period is set with an external resistor connected from the TMR pin to ...
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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 ...