Intermec 073290-001 User Manual

The charging current is applied through the contacts on the base of the 
battery; the 26-pin dock connector is not used for charging. See “AD1 
Charging” on page 99 for details on the charging circuit in the dock. 

A 10-farad 2.5V supercap (C89) provides backup current to hold the 
machine state while the main battery is being replaced. If the battery is 
removed without first suspending the CK30, a fully charged supercap can 
provide enough current to run the CK30 at full power for up to 1 second 
as it suspends, and still maintain the machine state for up to 10 minutes 
(at 25°C).  

The supercap voltage is boosted to 3.2V by switching converter U44 and 
routed to the main 3.3V bus. Switcher U44 is always on but draws very 
little current as long as the main 3.3V supply (U39) exceeds U44 3.2V 
output.  

While the CK30 is still on, signal PWR_EN* holds U44 MODE pin low 
(constant frequency mode), increasing its efficiency under heavy load.  
Once the system suspends, PWR_EN* goes high, selecting U44 burst 
mode for higher efficiency under a light load. 

C89 is charged at a constant 2.5V through LDO U50.  Power Supply 
Controller U38 enables supercap charging as long as main battery voltage 
is ≥ 5.1V. 

While the CK30 is docked in an AD1, AD2, or AC2, the dock provides 
12V operating current through Pin 3 on the base of the battery. The 
battery pack internal logic biases off the battery voltage, sending the Pin 3 
voltage from the dock to the CK30 while the battery charges. 

DC voltage applied to the CK30 must not exceed 15 VDC.