[AK4675]
■ Charge Pump Circuit
The charge pump operates by the output of a regulator which uses PVDDA voltage. The negative power supply (PVEE)
for headphone amplifiers is generated from internal charge pump circuit. The internal charge pump circuit generates
negative voltage from PVDDA voltage. The generated voltage (PVEE) is used to headphone amplifiers. When PMCP bit
is set to “1”, the charge pump circuit is powered-up. PMVCMA and PMOSC bits must be set to “1”.
PMOSC and PMVCM bits should be set to “1” when OSCN bit is “0”. PMVCM bit should be set to “1” and PMOSC bit
set to “0” when OSCN bit is “1”. The power-up time of charge pump circuit is typically 6.2ms and maximum 10ms at
OSCN bit = “0”. when OSCN bit = “1”, the power-up time is shown in Table 79. When PMHPL or PMHPR bit is set to
“1”, the Headphone-Amp is powered-up after the charge pump circuit is powered-up. Figure 87 shows the power-up
sequence.
MSEL bit
0
MCKIA Freq
2.048MHz
2.8224MHz
3.072MHz
Power-Up Time
6m (12288/MCKIA)
6.5ms (18432/MCKIA)
6ms (18432/MCKIA)
1
Table 79. Charge Pump Circuit Power-Up Time (OSCN bit = “1”)
■ Transition Time
PUT1-0 bits set the power-up/down time of headphone-amp and PTS1-0 bits set the mute ON/OFF time of
headphone-amp. These operations are soft transition.
MOFF bit set the Enable/Disable for the soft transition. The soft transition is disabled while these bits are “1”, and
ON/OFF is switched immediately.
As shown in Table 80, if the soft transition is enabled, the register value of same address must be changed by an interval
more than transition time. The write operation is ignored if the same values are written as the previous write operation.
Address
0DH
Register Name
HPMTN bit
Enable / Disable
MOFF bit
PTS1-0 bits
Table 80. Registers with Transition Time
MUTE ON/OFF Time
PTS1
PTS0
OSCN bit = “0”
OSCN bit = “1”
typ.
max
MSEL bit= “0”
MSEL bit = “1”
0
0
1
1
0
1
0
1
16.4ms
32.8ms
65.6ms
131.2ms
26.3ms
51.5ms
105.0ms
210.0ms
32768/MCKIA
65536/MCKIA
131072/MCKIA 196608/MCKIA
262144/MCKIA 393216/MCKIA
49152/MCKIA (default)
98304/MCKIA
Table 81. Headphone-Amp Mute ON/OFF Transition Time
MS0963-E-00
2008/05
- 111 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
