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File name: | bq24400.pdf [preview ] |
Size: | 270 kB |
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Descr: | NiCd/Ni MH Battery Charger |
Group: | Electronics > Automobile > Electrical diagram |
Uploaded: | 02-02-2007 |
User: | Puff |
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File name bq24400.pdf bq24400 Programmable NiCd/NiMH Fast-Charge Management Device Features Ø Safe management of fast charge for NiCd and NiMH battery packs. High-frequency switching controller for efficient and simple charger design Pre-charge qualification for detecting shorted, damaged, or overheated cells Fast-charge termination by peak voltahge (PVD), maximum temperature, and maximum charge time Selectable top-off mode for achieving maximum capacity in NiMH batteries Programmable trickle-charge mode for reviving deeply discharged batteries and for postcharge maintenance Built-in battery removal and insertion detection Sleep mode for low power consumption General Description The bq24400 is a programmable, monolithic IC for fast-charge management of nickel cadmium (NiCd) and nickel metal-hydride (NiMH) batteries. The bq24400 provides a number of charge termination criteria: l Ø Ø Peak voltage, PVD (for NiCd and NiMH) Maximum temperature Maximum charge time For safety, the bq24400 inhibits fast charge until the battery voltage and temperature are within user-defined limits. If the battery voltage is below the low-voltage threshold, the bq24400 uses trickle-charge to condition the battery. For NiMH batteries, the bq24400 provides an optional top-off charge to maximize the battery capacity. The integrated high-frequency comparator allows the bq24400 to be the basis for a complete, high-efficiency power-conversion circuit. Ø l l Ø Ø Ø Ø Pin Connections Pin Names SNS VSS Current-sense input System ground Charge-status output Battery-voltage input TS RC VCC MOD Temperature-sense input Timer-program input Supply-voltage input Modulation-control output SNS VSS LED BAT 1 2 3 4 8 7 6 5 MOD VCC RC TS LED BAT 8-Pin DIP or Narrow SOIC or TSSOP PN-2000.eps SLUS498 -SEPTEMBER 2001 1 bq24400 Pin Descriptions SNS Current-sense input Enables the bq24400 to sense the battery current via the voltage developed on this pin by an external sense-resistor connected in series with the battery pack. VSS LED System Ground Charge-status output Open-drain output that indicates the charging status by turning on, turning off, or flashing an external LED. BAT Battery-voltage input Battery-voltage sense input. A simple resistive divider, across the battery terminals, generates this input. TS Temperature-sense input Input for an external battery-temperature monitoring circuit. An external resistive divider network with a negative temperature-coefficient thermistor sets the lower and upper temperature thresholds. TS RC Timer-program input RC input used to program the maximum charge-time, hold-off period, and trickle rate during the charge cycle, and to disable or enable top-off charge. VCC MOD Supply-voltage input Modulation-control output Push-pull output that controls the charging current to the battery. MOD switches high to enable charging current to flow and low to inhibit charging- current flow. Functional Description The bq24400 is a versatile, NiCd, NiMH battery- char |
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