BQ2005 Datasheet | Benchmarq

Fast-Charge IC for Dual Battery Packs Features ∗ Sequential fast charge and con d-i tioning of two Ni Cd or Ni MH nickel cadmium or nickel-metal hydride bat tery packs ∗ Hysteretic PWM switch-mode cur rent regulation or gated control of anexternalregulator ∗ Easily integrated into systems or used as a stand-alone charger ∗ Pre-charge qual i fi ca tion of tem per ature and volt age ∗ Direct LED outputs dis play bat tery and charge sta tus ∗ Fast-chargeterminationby ∆ temperature/∆ time, -∆V, max i mum volt age, max i mum tem per a ture, and max i mum time ∗ Optional top-off and pulse-trickle charging General Description The bq2005 Fast-Charge IC provides prehensive fast charge control functions together with high-speed switching power control circuitry on a monolithic CMOS device for sequential charge man age ment in dual battery packapplications. In te gra tion of closed-loop cur rent control circuitry allows the bq2005 to be the basis of a cost-effective solution for stand-alone and sys tem-integrated charg ers for bat ter ies of one or more cells. Switch-activated dis-charge-before-charge allows bq2005-based chargers to support battery conditioning and capacity determ-i nation. High-efficiency power con ver sion is acplished using the bq2005 as a hysteretic PWM controller for switch-mode regulation of the charging cur rent. The bq2005 may alternatively be used to gate an externally reg ulated charging cur rent. Fast charge may begin on ap pli ca tion of the charg ing sup ply, re place ment of the battery, or switch depres sion. For safety, fast charge is in hib ited unless/un til the bat tery tem per a ture and volt age are within con fig ured lim its. Temperature, voltage, and time are monitored throughout fast charge. Fast charge is ter mi nated by any of the fol low ing: n Rate of temperature rise ( ∆T/∆t) n Negative delta voltage (-∆V) n Maximumvoltage n Maximumtemperature n Maximumtime Af ter fast charge, op tional top-off and pulsed current...