PT8A2712

Product Description

The PT8A2707-12/2717-19 integrates charger controller and fuel-gauge into a single-chip. It detects full-charge through -V, dT/dt, safety-timer and maximum battery voltage, and learns the battery capacity from each charging/discharging cycle. Since PT8A2707-12/2717-19 measures charge/discharge current to account for the battery capacity in/out respectively, the battery capacity can be accurately recorded and displayed in 6-level (10%/20%/40%/60%/80%/100%) LED or LCD pattern. The continuous-learning capability enables the devices to take care of battery aging effect so that the capacity level is always accurately displayed throughout the life-span of the battery pack. In the charging control, a DC/DC controller is regulated to regulate constant currents for pre-charge, fast charge and trickle-charge conditions. The charging current is determined by the value of a current-sense resistor such that it is tunable upon different applications requirements. When motor is turned on during charging, the charge current to battery pack is regulated at 1/10 of the fast-charge current so that motor can draw current from the adapter while battery is charged in a safe and under-controlled condition. The PT8A2707-12/2717-19 employs NTC as the means to measure the battery pack temperature. When a high temperature is measured during charging, the charging current will be cut off. The devices also detect NTC short/open at which all activities will be disabled if any one of these conditions is observed.

Features

• 2-3 cells, NiCd or NiMH battery fast-charger controller for battery-embedded devices
• Precise 7-bit fuel-gauge-counter measures charging and discharging current through battery pack. Make it possible to accurately indicate battery capacity through LCD (PT8A2707-09/2717-19) or LEDs (PT8A2710-12).
• Integrated with a DC/DC step-down controller make it possible for customers to manufacture just one PCB module that can:
• Cover different product models that requires different charging current/speed by changing only one resistor
• Work with different kinds of AC/DC adapters with wide input voltage ranges.
• Motor also can work in both corded or cordless conditions. When motor is used in cord-mode, the charging current to battery is regulated at a maximum value of 1/10 of the fast-charging current. The battery is just like being slowly-charged and prevented from being exposed to a prolonged high-current charging profile.
• Provide excellent charge and discharge protections.
• Available with different parts to cover products employing slide switch (PT8A2707/10/17), tact switch (PT8A2708/09/11/12/18/19) input to control motor ON/OFF. Two-step motor-speed control (70%, 100%) is also available in PT8A2708/2711/2718.
• Very low standby current of typical 20μA. Products could typically work in standby-mode for a few months, depends on battery capacity.

Technology Highlights

• Employing 5 major charging states: cool-down / pre-charge / fast charge / trickle charge / stop charge, taking the best care for different battery conditions, especially for aged or dry batteries
• Excellent battery protection and full-charge detection schemes
• Negative delta voltage detection (-ΔV) with precision of +/-1mV step
• Maximum battery voltage detection to turn to maintenance
• Rate of change of temperature detection (dT/dt) best for NiMH batteries full-charge termination (use with NTC)
• Abnormal high battery temperature (55°C) detection to stop charging (use with NTC)
• Flexible fast charge time-out setting (30mins/60mins/90mins/150mins)
• Fuel-gauge counter takes into account the battery self-discharge compensation based on time.
• Provide excellent battery over-discharge protection through auto-stop motor at once (<0.2s) when
• discharging current is higher than preset limit value for 3sec (3 limit values selectable externally)
• battery pack voltage is lower than No-Power value (adjustable externally)
• NTC measures battery pack temperature higher than preset high-temp value(adjustable externally)
• Key delay to reject multiple inputs at Tact switch (about 0.125s ignorance).
• Internal voltage regulator provides better rejection to interference.
• Integrated DC/DC step-down controller to regulate constant charging currents at different charging
• Available with 24-pin SOIC and SSOP lead-free package