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15. Power Supply Circuit (POWER)
15.1
Overview
In the different voltage regulator circuits of the OPTION C and OPTION D, the battery voltage (V
to generate the voltage V
output voltage of this halver circuit
voltage, thereby suppressing the supply current. However, the battery voltage is connected directly to the power
supply of the high-speed clock generator circuit.
In the different voltage regulator circuits of the OPTION A and OPTION B, the battery voltage is connected
directly to the power supply line and the different driving voltages are generated internally from this voltage.
The following three voltage regulator circuits are incorporated in the OPTION B and OPTION D:
(1) V/R1:
Output voltage = 1.15 V
... The voltage regulator circuit generating the power supply voltage (V
and other internal logic circuits.
(2) V/R2:
Output voltage = 0.7 V
... The voltage regulator circuit generating the power supply voltage (V
generator circuit.
(3) V/R3:
Output voltage = 0.95 V
... The voltage regulator circuit generating the reference voltage (V
circuit.
The following two voltage regulator circuits are incorporated in the OPTION A and OPTION C:
(1) V/R1:
Output voltage = 1.15 V
... The voltage regulator circuit generating the power supply voltage (V
and other internal logic circuits.
(2) V/R2:
Output voltage = 0.7 V
... The voltage regulator circuit generating the power supply voltage (V
generator circuit.
!
Note:
*1: The power supply voltage (V
OPTION A and OPTION B: V
OPTION C and OPTION D: V
*2: The halver circuit can be used in OPTION C and OPTION D (but cannot be used in OPTION A and OPTION B).
15.1.1 Precautions in Using the Halver Circuit
The halver circuit can be used in OPTION C and OPTION D. The halver circuit can operate when V
3.6 V. Depending on the battery load of the application system being used, it is possible to select by software to
supply either the output voltage of the halver circuit or the battery voltage to the different voltage regulator
circuits. It is possible to suppress the supply current during operation by efficiently using the halver circuit
output voltage.
The software setting should be made so that the output voltage of the halver circuit is supplied to the different
voltage regulator circuits during normal load, and the battery voltage is supplied to the different voltage regulator
circuits during heavy load (such as when the backlight is lit).
Normal load is when V
Further, it is possible to select by software a judgment threshold voltage of 2.6 V, 2.4 V, 2.0 V, or 1.8 V for the
BDL (battery low detection) function.
OPTION A (C): 1.5 V (3.0 V), Without regulator
circuit for LCD bias
, which is then used to generate internally the different driving voltages. By using the
HF
*2
, it is possible to drive the internal circuit operations at half the battery
) supplied from outside should be within the following recommended ranges:
DD
= 1.3 to 1.7 V
DD
= 1.8 to 3.6 V
DD
is 2.4 to 3.6 V, and heavy load is when V
DD
Chapter 15 Power Supply Circuit (POWER)
is less than 2.4 V.
DD
15 – 1
OPTION B (D): 1.5 V (3.0 V), With regulator
ML63611 User's Manual
*1
)
is halved
DD
) for the CPU, ROM, RAM,
CH
) for the low-speed clock
XT
) for the LCD bias generator
DD1
) for the CPU, ROM, RAM,
CH
) for the low-speed clock
XT
is 2.4 to
DD
circuit for LCD bias
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