Intermec 073290-001 User Manual

Temperature monitoring is done using a voltage divider formed by R1, 
R17 and a NTC thermistor (RT1). 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 will 
begin. 

When a charge cycle begins, pin 14 on the BQ2954 is modulated at 
100kHz. This pin controls a buck switcher formed by Q6, D1, 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 (+100 mV–10 mV) 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/15) is reached. At this point charge current is 
terminated and the charge cycle is complete. 

The AC1 requires 12 VDC at 4A. The 073573 power supply is qualified 
for use with the AC1. 

The AC2 can charge four CK30 units at the same time. The AC2 uses the 
same PCB as the AD2. The only difference is that all communications 
related circuitry has been removed. The only function of the AC2 is to 
charge the battery of up to four CK30s simultaneously. 

A CK30 that is inserted into the AC2 is powered directly from the 12V 
supply. J6, J14, J22, and J30 are the contacts by which power is transferred 
to each of the four CK30s. 

The charging design is the same as the AD2. Refer to “AD2 Charging” for 
a detailed description of the charging algorithm. 

The AC2 requires 12 VDC at 4A. The 073573 power supply is qualified 
for use with the AC2.