User`s guide

Rev. 1.10 106 November 14, 2014 Rev. 1.10 107 November 14, 2014
HT66FW2230
Wireless Charger A/D Flash 8-Bit MCU
Demodulation Function
TheDemodulatordemodulatesthecommunicationsignalfromthereceiverend.
OPA
CMP
COMM0
2.2M
100K0.1uf
10K
4.7nF
4.7nF
10K
10K 680K
100k
Signal after
demodulation
( bias 2V)
HT66FW2230
AN AX CP CN CX
Filter
Interrupt
COMM0
Analog
Mux
COMM1
COMM2
DEMO pad
MCU
reading
AIS[1:0]
8 bit
DAC
C
D[7:0]
Filter
Filter
clock
R1
R2
A
(R1=4K)
G=1/5/10/15/20/30/40/50
S1
S0
S2
S3
G[2:0]
FLT[2:0]
f
FLT
=f
H
/4
M[1:0]
AN8
AN
AX
CP CN
CX
DMS3
DMS2
DMS1
DMS0
Demodulator Circuit
Demodulator Circuit Operation
ThedemodulatorinputissourcedfromCOMM0~COMM2,selectedusingtheAIS1~AIS0bitsin
theDCMISCregister.Afterthis,fourswitchesS0~S3,areusedformodeselection.AnOPAMPand
tworesistorsareusedtoformaPGAfunction.ThePGAgaincanbepositiveornegativedetermined
bytheinputvoltageconnectedtothepositiveinputornegativeinputofthePGA.DEMREFisused
togeneratereferencevoltage.Thecomparatorcomparesthisreferencevoltagewiththeamplied
output.FinallythecomparatoroutputisfilteredtogenerateDEMOandDEMINT.Theseare
debouncedversionsofDEMCXwhichareusedtoindicatewhetherthesourcecurrentisoutwiththe
specicationornot.DEMOisdenedasthedemodulatoroutputandDEMINTisthedemodulator
interrupttrigger.
Notethatthelterclock;f
HXT
istheHXTclock.Theampliedoutputvoltagealsocanbereadout
bymeansofanotherADCfromDEMAX.TheDACoutputvoltageiscontrolledbytheDEMREF
registerandtheDACoutputisdenedas
DACV
OUT
=(DACV
REF
/256)×DEMREF[7:0](1)