IC BQ 24740 skema

by : lhagus813@gmail.com

 

IC BQ 24740 

Host-controlled Multi-chemistry Battery   Charger with Low Input Power Detect
FEATURES
•                                            NMOS-NMOS Synchronous Buck Converter
with 300 kHz Frequency and >95% Efficiency
•                                            30-ns Minimum Driver Dead-time and 99.5%
Maximum Effective Duty Cycle
•                                            High-Accuracy Voltage and Current
                                             Regulation
–                                            ±0.5% Charge Voltage Accuracy
–                                            ±3% Charge Current Accuracy
-                                            ±3% Adapter Current Accuracy
-                                            ±2% Input Current Sense Amp Accuracy
•                                            Integration
–  Internal Loop Compensation
-  Internal Soft Start
•                                            Safety
–  Input Overvoltage Protection (OVP)
-  Dynamic Power Management (DPM) with
Status Indicator
-  Reverse-Conduction Protection Input FET
•                                            Supports Two, Three, or Four Li+ Cells
•                                            5 - 24 V AC/DC-Adapter Operating Range
•                                            Analog Inputs with Ratiometric Programming
via Resistors or DAC/GPIO Host Control
-  Charge Voltage (4-4.512 V/cell)
-  Charge Current (up to 10 A, with 10-mΩ
sense resistor)
-  Adapter Current Limit (DPM)
•                                            Status and Monitoring Outputs
-  AC/DC Adapter Present with
Programmable Voltage Threshold
-  Low Input-Power Detect with Adjustable
Threshold and Hysteresis
-  DPM Loop Active
-  Current Drawn from Input Source
•                                            Battery Discharge Current Sense with No
Adapter, or Selectable Low-Iq mode
•                                            Supports Any Battery Chemistry: Li+, NiCd,
                                             NiMH, Lead Acid, etc.
•                                            Charge Enable
•                                            10-µA Off-State Current
•                                            28-pin, 5x5-mm QFN package
 

APPLICATIONS
•  Notebook and Ultra-Mobile Computers
•  Portable Data-Capture Terminals
•  Portable Printers
•  Medical Diagnostics Equipment
•  Battery Bay Chargers
•  Battery Back-up Systems
DESCRIPTION
The   bq24740   is   a   high-efficiency,   synchronous
battery  charger  with  integrated  compensation  and
system power selector logic, offering low component
count  for  space-constrained  multi-chemistry  battery
charging  applications.  Ratiometric  charge  current
and voltage programming allows very high regulation
accuracies,   and   can   be   either   hardwired   with
resistors                                                  or   programmed     by     the     system
power-management microcontroller using a DAC or
GPIOs.
The bq24740 charges two, three, or four series Li+
cells, supporting up to 10 A of charge current, and is
available in a 28-pin, 5x5-mm thin QFN package.
 

 

 

DESCRIPTION (CONTINUED)
The bq24740 features Dynamic Power Management (DPM) and input power limiting. These features reduce
battery  charge  current  when  the  input  power  limit  is  reached  to  avoid  overloading  the  AC  adapter  when
supplying the load and the battery charger simultaneously. A highly-accurate current-sense amplifier enables
precise measurement of input current from the AC adapter to monitor the overall system power. If the adapter
current is above the programmed low-power threshold, a signal is sent to host so that the system optimizes its
power performance according to what is available from the adapter.