Intermec 073290-001 User Manual

The AD1 charges a single CK30 battery while on the unit. It also provides 
a DB9 male connector for serial communications, an 8-pin RJ45 
connector for 10/100 Ethernet communications, a Type-B USB connector 
for USB communications and a 26-pin JAE connector for interfacing with 
the CK30. Refer to “Connector Pin-Outs” on page 96 for the connector 
pin-outs. All of these communication methods are handled by the CK30; 
the connectors on the AD1 are simply used for passing the signals to and 
from the CK30. 

The 26-pin JAE connector is a right-angle connector that is mounted on a 
separate PCB; it interfaces to the AD1’s main PCB through two 10-pin 
headers (J4 and J5). 

A CK30 that is inserted into the AD1 is powered directly from the 12V 
supply. J9 is the contact by which power is transferred to the CK30. 

U1 (TI BQ2954) controls all aspects of charging for the AD1. It uses a 
constant current/constant voltage-charging algorithm. The AD1 is 
designed to charge the CK30 battery pack with a maximum charge current 
of 1.25A. The sense resistor (R15) is what sets the maximum charge 
current (Imax = 250 mV/R15). The AD1 is also designed to only allow 
charging between 0ºC and 45ºC ±7ºC. A battery that has been discharged 
through normal use on a CK30 recharges in less than three hours on the 
AD1. 

J10, J11, and J12 are the contacts by which the CK30 battery interfaces to 
the charging circuitry. The voltage divider formed by R16 and R17 is used 
to notify the BQ2954 that a battery has been inserted. It is also used to 
determine whether to begin charging based on the battery voltage and an 
internal reference voltage in the BQ2954. 

Temperature monitoring is done using a voltage divider formed by R18, 
R19 and a NTC thermistor (R23). If the battery voltage is at a value that 
the BQ2954 identifies as being below the reference voltage, and the 
ambient temperature is within acceptable limits then a charge cycle begins. 

When a charge cycle begins, pin 14 on the BQ2954 is modulated at 
100kHz. This pin controls a buck switcher formed by Q4, D5 and L2. 
This switcher is set to provide a constant 8.4 VDC from the 12 VDC 
supply. Once the battery has reached 8.4V (+100mV -10mV) then the 
BQ2954 switches to the constant voltage phase of the charge cycle.  
During this phase the BQ2954 slowly ramps down the charge current 
until the designed trip point (Imax/20) is reached. At this point charge 
current is terminated and the charge cycle is complete. 

The BQ2954 uses the current mirror (U6) to measure the charge current. 
This measurement is used to compare against the designed trip point 
(Imax/20).