Low power operation method for apparatus having data transmission rate
A low power operation method provides an apparatus with a data transmission rate. A power management unit (PMU), which is not influenced by voltage, process, and temperature, biases a high frequency oscillator (HOSC) and makes the HOSC generate a steady and high precision clock. The clock of the HOSC is used to modify a timing length of a timer which is referenced by a low frequency oscillator (LOSC) without PMU. At last, through the modified timing length, the apparatus achieves high precision periods and data transmissions with compensation for voltage, process, and temperature. Thus, the data transmission cycles of the apparatus maintain stable and robust even if the apparatus applies duty cycle usage of the HOSC and the PMU for reducing power consumption with actions of turning on and turning off. Consequently, the periodic apparatus maintains data transmission rate with the low power consumption advantage of non-periodic apparatus.
1. A low power operation method for an apparatus having a data transmission rate,
wherein the method is applied with a main apparatus, which comprises a first frequency oscillator (high-frequency oscillator, HOSC), a second frequency oscillator (low-frequency oscillator, LOSC), a power management unit (PMU), a timer, and a regulator; and
wherein the method comprises steps of:
(a) obtaining a base frequency of said main apparatus, wherein said base frequency is a known constant being a ratio of an ideal frequency of said first frequency oscillator to an ideal frequency of said second frequency oscillator;
(b) turning on said PMU and said first frequency oscillator;
(c) loading a data transmission rate, which is set by a user, to said timer as an initial timing length; then, in said regulator, calculating an actual period of said second frequency oscillator through said first frequency oscillator to obtain an actual frequency ratio, which is shifting, as a real frequency; and, at last, through processing calculation with said regulator, multiplying a ratio of said base frequency to said real frequency by said initial timing length to obtain a valid timing length of said timer;
(d) awaiting said main apparatus to enter into a sleeping mode;
(e) turning off said PMU and said first frequency oscillator; and,
(f) after said timer processes timing until reaching said valid timing length, turning back to step (b) to process a next cycle of step (b) to step (f) continuously.
2. The method according to claim 1 ,
wherein said first frequency oscillator is a high frequency oscillator compensated and biased by said PMU; and, during functioning said PMU, a steady state is obtained without being influenced by voltage, process, and temperature.
3. The method according to claim 1 ,
wherein said second frequency oscillator is a low-frequency oscillator non-compensated and has a changing status influenced by voltage, process, and temperature.
4. The method according to claim 1 ,
wherein, on turning on said PMU, comprising a bandgap, a low dropout regulator (LDO), and a compensator, by said timer, bias and compensation are processed to said first frequency oscillator according to voltage, process, and temperature.
5. The method according to claim 1 ,
wherein, in step (c), said real frequency is a ratio of an actual frequency of said first frequency oscillator to an actual frequency of said second frequency oscillator.
6. The method according to claim 1 ,
wherein, said main apparatus is of a busy mode in step (b) to step (e) and is of said sleeping mode in step (f).