BQ2004E Status: ACTIVE

Product Information

Features

• Fast charge and conditioning of nickel cadmium or nickel-metal hydride batteries
• Hysteretic PWM switch-mode current regulation or gated control of an external regulator
• Easily integrated into systems or used as a stand-alone charger
• Pre-charge qualification of temperature and voltage
• Configurable, direct LED outputs display battery and charge status
• Fast-charge termination by V, maximum voltage, maximum temperature, and maximum time
• Optional top-off charge and pulsed current maintenance charging
• Logic-level controlled low-power mode (< 5uA standby current)

Description

The bq2004E and bq2004H Fast Charge ICs provide comprehensive fast charge control functions together with high-speed switching power control circuitry on a monolithic CMOS device.

Integration of closed-loop current control circuitry allows the bq2004 to be the basis of a cost-effective solution for stand-alone and system-integrated chargers for batteries of one or more cells.

Switch-activated discharge-before-charge allows bq2004E/H-based chargers to support battery conditioning and capacity determination.

High-efficiency power conversion is accomplished using the bq2004E/H as a hysteretic PWM controller for switch-mode regulation of the charging current. The bq2004E/H may alternatively be used to gate an externally regulated charging current.

Fast charge may begin on application of the charging supply, replacement of the battery, or switch depression. For safety, fast charge is inhibited unless/until the battery temperature and voltage are within configured limits.

Temperature, voltage, and time are monitored throughout fast charge. Fast charge is terminated by any of the following:

• Rate of temperature rise (t)
• Peak voltage detection (PVD)
• Negative delta voltage (-V)
• Maximum voltage
• Maximum temperature
• Maximum time

After fast charge, optional top-off and pulsed current maintenance phases with appropriate display mode selections are available.

The bq2004H differs from the bq2004E only in that fast charge, hold-off, and top-off time units have been scaled up by a factor of two, and the bq2004H provides different display selections. Timing differences between the two ICs are illustrated in Table 1. Display differences are shown in Table 2.