Cypress AN2309, CY8C29x66, CY8C24794 specifications Cell-Balancing Algorithm

AN2309

The minimum cell-balance parameter consists of the voltage measure error value plus the internal impedance error value.

The cell-balancing algorithm that is implemented here does not significantly lengthen the charge time. The charger monitors all of the cell voltages. Cell balancing is performed during both phases and it is realized in one common module. The cell- balancing algorithm is represented in Figure 11. The cell-balancing profile examples are shown in the Appendix, Figure 14 on page 19 and Figure 15 on page 20.

Figure 11. Cell-Balancing Algorithm

Start

Chagre Off

Balancing Reset

DoCellBalancing = FALSE

	Wait Start Delay
	Measure Vb1, Vb2
	Calc Vbmin, Vbmax, dV
No		Yes
	Is Discharge State?

Chagre On
Are cells Not	No
Balanced?
Vbmax-Vbmin>dVch_balmin
Yes
Check Out Of The	Yes
Minimum Cell
Balancing Current
isCV and Ich<Ibalmin
No
DoCellBalancing = TRUE

Are Cells Not	No
Balanced?
Vbmax-Vbmin>
dVdisch_balmin
Yes
Check Out Of	Yes
The VMID Voltage
Vbmax<Vmid
No
DoCellBalancing = TRUE

No

Balancing Cell 2

No

Is DoCellBalancing?

Yes

Yes

Vb1>Vb2

Balancing Cell 1

Send Debug Data

Wait End Delay

End

November 25, 2007 Document No. 001-17394 Rev. *B - 15 -

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