SAA8200HL Datasheet, PDF (48/71 Pages) NXP Semiconductors – Ensation Base integrated wireless audio baseband

Philips Semiconductors
SAA8200HL
Ensation Base integrated wireless audio baseband
V_{BAT(DCDC) bias}
clk
VOUT[1,2] DCDC[1,2]_ADJUST[2
VTH[1,2]
comparator
comparator
VTL[1,2]
7×
V_ss
V_ref
V_ss(clean)
001aac004
Fig 16. Analog part of the controller
See Figure 17 for a coil current cycle in continuous mode. The average coil current is
equal to the average current demanded by the load. The lengths of t1 and t2 are
determined by the battery voltage and the output voltage of the DC-to-DC converter. The
output voltage is allowed to vary within a certain window. This means that there will be a
voltage ripple with a frequency that is largely correlated to the frequency content of the
load current. The peak-to-peak amplitude of the ripple will be more or less equal to the
window height. There will be ripple at the switching frequency too, this is mainly caused by
the fact that the coil current will run through parasitic resistances of the load circuit.
I_L
(A)
t1
t2
t1
SAA8200HL_2
Preliminary data sheet
Fig 17. Coil current cycle in continuous mode
Rev. 02 — 17 October 2005
t (s)
t2
t1
001aac005
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
48 of 71