ADC and power consumption

[bogdan]

I have a project based on a pic16f913 to open (unlock) a box of cigarettes after a certain period of time.

parts used:
-LM2936 (LDO Voltage Regulator 5V)
-dumb LCD for countdown
-BD6222 (H-Bridge to control the latching solenoid)

The consumtion on SLEEP of the circuit is somewhere close by 42uA

When i add the ADC to check the battery the consumtion increase to 390uA (with the ADC off.....ADCON0.0=0).

'CHECK THE BATTERY VOLTAGE

TRISA.0 = 1                                   'set PORTA.0 to input
ANSEL.0 = 1                                   'set PORTA.0 to analog
ADCON0.7 = 1                                  'A/D result have to be right justified for 10 bits (2^10=1024)resolution (ADFM bit)
ADCON0.6 = 0                                  'set voltage_reference=Vss (VCFG1 bit)
ADCON0.5 = 0                                  'set voltage_reference=Vdd (VCFG0 bit)

ADCON0.4 = 0                                  'set analog_channel=AN0=PORTA.0 (CHS bits)
ADCON0.3 = 0
ADCON0.2 = 0

ADCON1.5 = 1                                  'set A/D conversion clock source to F_rc=dedicated internal osc (ADCS bits)
ADCON1.4 = 1

ADCON0.0 = 1                                  'enable A/D module
PAUSE 4                                       'wait 0.5sec (...acquisition time)  (32768*500/4000000)
'start_adc_conversion:
FOR readADCloop=8 TO 1 step -1
   ADCON0.1=1                                'start A/D conversion  (GO/DONE bit)
    WHILE ADCON0.1=1                          'wait for it to complete
    WEND
                                                     
    VbatTEMP.HighByte = ADRESH                'read high-byte of result
    VbatTEMP.LowByte = ADRESL                 'read low-byte of result
    Vbat=Vbat+VbatTEMP
    PAUSEUS 13                                'wait 10msec (10000*32768/4000000)
NEXT readADCloop



SELECT CASE Vbat
    CASE IS < 500
        END                                   'battery is too low to drive the solenoid=END THE PROGRAM
    CASE IS < 900                             'attention: battery low
        LCDDATA10.5 = 1                       'write to lcd "b" (as in Battery low)
        LCDDATA4.5 = 1
        LCDDATA7.5 = 1
        LCDDATA4.6 = 1
        LCDDATA1.5 = 1
END SELECT    

ADCON0 = 0                                    'disable A/D module

It is normal just one ADC to increase the consumtion so much ???

Im sure is something wrong with my setup / code

Please just take a look... Thank You