WM8753L
Advanced Information
POWER MANAGEMENT
The WM8753L has three control registers that allow users to select which functions are active. For
minimum power consumption, unused functions should be disabled. To avoid any pop or click noise,
it is important to enable or disable functions in the correct order (see Applications Information).
VMIDSEL is the enable for the Vmid reference, which defaults to disabled and can be enabled as a
50kΩ potential divider or, for low power maintenance of Vref when all other blocks are disabled, as a
500kΩ potential divider.
REGISTER
ADDRESS
BIT
8:7
LABEL
DEFAULT
00
DESCRIPTION
R20 (14h)
Power
Management
(1)
VMIDSEL
Vmid divider enable and select
00 – Vmid disabled (for OFF mode)
01 – 50kΩ divider enabled (for
playback/record)
10 – 500kΩ divider enabled (for low-power
standby)
11 – 5kΩ divider enabled (for fast start-up)
6
VREF
0
VREF enable (necessary for all other
functions)
5
4
3
2
0
8
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
3
2
1
0
MICB
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
MIC Bias enable
Voice DAC enable
DAC Left enable
DAC Right enable
Disables MCLK into digital
Mic1 preamp enable
Mic2 preamp enable
ALC mixer enable
ADC left PGA enable
ADC right PGA enable
Left ADC enable
Right ADCR enable
RX mixer enable
Line mixer enable
LOUT1 enable
VDAC
DACL
DACR
DIGENB
MICAMP1EN
MICAMP2EN
ALCMIX
PGAL
R21 (15h)
Power
Management
(2)
PGAR
ADCL
ADCR
RXMIX
LINEMIX
LOUT1
ROUT1
LOUT2
ROUT2
OUT3
R22 (16h)
Power
Management
ROUT1 enable
LOUT2 enable
(3)
ROUT2 enable
OUT3 enable
OUT4
OUT4 enable
MONO1
MONO2
RECMIX
MONOMIX
RIGHTMIX
LEFTMIX
MONO1 enable
MONO2 enable
R23 (17h)
Power
Management
(4)
Record Mixer Enable
Mono mixer enable
Right mixer enable
Left mixer enable
Note: All control bits are 0=OFF, 1=ON
Table 69 Power Management
SAVING POWER AT LOW SUPPLY VOLTAGES
The analogue supplies to the WM8753L can run from 1.8V to 3.6V. By default, all analogue circuitry
on the device is optimized to run at 3.3V. This set-up is also good for all other supply voltages down
to 1.8V. However, at lower voltages, it is possible to save power by reducing the internal bias currents
used in the analogue circuitry. This is controlled as shown below.
AI Rev 3.1 June 2004
71
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
