KR20080073029A - Apparatus for providing voltage to portable device - Google Patents

Abstract

A voltage supply apparatus of a portable device is provided to allow an LDO(Low Drop Output) regulator to output a rated voltage of each device even in a low voltage of a battery. A voltage supply apparatus of a portable device includes a voltage compensating unit(310), a first voltage converting unit(320), and a second voltage converting unit(330). The voltage compensating unit converts voltage applied from a voltage supply source(300) into a voltage of a predetermined level to output the converted voltage. The first voltage converting unit converts the voltage of the predetermined level outputted from the voltage compensating unit to supply the rated voltage to a first device(340). The second voltage converting unit converts the voltage inputted from the voltage supply source to supply the rated voltage to a second device(350). The voltage supply source is a battery.

Description

Voltage supply for portable devices {APPARATUS FOR PROVIDING VOLTAGE TO PORTABLE DEVICE}

1 is a view showing an example of the configuration of a voltage supply device of a typical portable device.

2 is a graph showing an example of power consumption of a battery in FIG.

3 is a view showing an example of the configuration of a voltage supply device of a portable device according to the present invention.

4 is a graph showing an example of power consumption of a battery in FIG.

5A illustrates an example of the power efficiency in FIG. 1.

FIG. 5B illustrates an example of the power efficiency in FIG. 3. FIG.

* Explanation of symbols for main parts of the drawings

300: voltage source 310: voltage compensation unit

320: first voltage converter 330: second voltage converter

340: first device 350: second device

The present invention relates to a voltage supply device for a portable device that can efficiently use the power of the battery.

In general, a device includes devices (components), and the devices are driven by supplying different voltages, so that a voltage supply device for supplying a driving voltage to each device is provided in the device.

There are many types of voltage supply devices as described above, but DC / DC converters and LDO (Low Drop Output) regulators are commonly used.

The DC / DC converter is composed of an inductor, a transformer, a capacitor, etc., and takes up a lot of space on a circuit board, but the efficiency is generally 90% or more, and the input voltage is boosted or stepped down and output. The LDO regulator occupies less space with a smaller IC but has lower efficiency than a DC / DC converter, and outputs the input voltage by stepping down.

In the case of a portable device, a voltage supply device is a mixture of a DC / DC converter and an LDO regulator, and accordingly, the DC / DC converter and the LDO regulator receive a voltage from a battery and convert the voltage into different voltages. The voltage is supplied to the device, but the power efficiency is 80-90%, and the battery power is not fully used.

On the other hand, as the use of portable devices is rapidly increasing in recent years, there is an urgent need to maximize energy efficiency to use energy more efficiently.

However, portable devices have to be manufactured in small size, so there are many difficulties in maximizing power efficiency.

Accordingly, an object of the present invention is to provide a voltage supply device of a portable device that can increase the battery use time by using the power of the battery efficiently.

Another object of the present invention is to provide a voltage supply device for a portable device that enables the LDO regulator to output the rated voltage of each device even at the low voltage of the battery.

The voltage supply device of the portable device of the present invention for achieving this object, the voltage compensation unit for converting the voltage applied from the voltage supply source to a voltage of a predetermined level; And a first voltage converter configured to supply a rated voltage to the first device by converting a voltage of a predetermined level output by the voltage compensator.

And a second voltage converter configured to convert a voltage input from the voltage supply source and supply a rated voltage to the second device.

The voltage supply is characterized in that the battery.

The second voltage converter is characterized in that it comprises at least one DC / DC converter.

The voltage compensator is a DC / DC converter.

The first voltage converter includes at least one low drop output (LDO) regulator.

In addition, a voltage of a predetermined level output by the voltage compensator is a voltage obtained by adding a rated output voltage of an LDO regulator that outputs the highest voltage among the at least one or more LDO regulators and a drop out voltage generated by the LDO. It is characterized by.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

However, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

1 is a view showing an example of a configuration of a voltage supply device of a general portable device, Figure 2 is a graph showing the power consumption of the battery in Figure 1 as an example.

Referring to FIG. 1, a voltage supply device of a portable device includes a first voltage converter 120 and a second voltage converter 130, and the first voltage converter 120 and the second voltage converter 130. 130 receives DC power output from the voltage supply source 100 through the power rail 105 and supplies driving power to the first device 140 and the second device 150.

The voltage source 100 is a battery that stores DC power and may be used for single use or alternately charging and discharging.

In more detail, the battery is provided in a vehicle or a portable device, and serves to supply power required for driving the vehicle or portable device to a voltage supply device. Batteries are classified into nickel cadmium (Ni-cd), nickel hydrogen (Ni-MH), and lithium-ion (Li-ion), depending on the chemicals that make up the battery. In addition, since the output voltage, size and shape vary, the user selects a battery or uses a predetermined battery according to the intended use. As a representative mobile phone, for example, the battery provided in the mobile phone may vary in shape depending on the make and model, but in general, the rated voltage is DC 3.6 to 3.7V, DC 4.2V is fully charged, and DC 3.0V Is in a discharged state. Accordingly, the mobile phone is driven by a voltage of approximately 4.2 to 3.0V DC from the battery.

Here, in the future, there are various types of batteries of the mobile phone device, but for the purpose of explanation, the battery provided in the mobile phone will be described as an example. In addition, it is preferable that DC power can be received from the outside in addition to the battery.

The first voltage converting unit 120 and the second voltage converting unit 130 need a DC power voltage received from the voltage supply source 100 at the first device (including the logic circuit) and the second devices 140 and 150. It converts the voltage into a voltage to supply the converted voltage to the device (140, 150).

The first voltage converter 120 converts the voltage of the DC power input when the DC power is input from the voltage supply source 100 into a voltage required by the first device 140, and converts the converted voltage into the voltage required by the first device 140. Supply to the first device 140.

Looking at the first voltage converter 120 in more detail, it is a plurality of LDO regulator (Low Drop Output regulator) for stepping down and outputting the voltage of the DC power input from the voltage supply source 100 to each predetermined voltage. . As a result, the voltage inputted by the plurality of LDO regulators is converted to supply the rated voltage to the first device 140. The LDO regulator is a small chip included in various types of regulator ICs. The LDO regulator solves the problem of occupying space, which is a problem of the DC / DC converter described above, but has a problem in that efficiency is lower than that of the DC / DC converter. The advantage of the LDO regulator is that it operates even if the difference between the input voltage and the output voltage is about 0.2 ~ 0.3V and outputs a preset voltage according to the input voltage. Meanwhile, the efficiency of the LDO regulator is regarded as the ratio of the input voltage and the output voltage, so the greater the difference between the input voltage and the output voltage, the lower the efficiency. As an example, the efficiency of the LDO regulator is the lowest and the unnecessary power consumption is increased at 4.2V of the battery's initial full charge voltage.

The second voltage converter 130 converts the voltage of the DC power input when the DC power is input from the voltage supply source 100 into a voltage required by the second device 150, and converts the converted voltage into the voltage required by the second device 150. Supply to the second device 150.

Looking at the second voltage converter 130 in more detail, a plurality of DC-DC converter (step-to-step down) to step up or down the voltage of the DC power input from the voltage supply source 100 to each predetermined voltage (DC-DC converter) to be. That is, the second voltage converter converts the input voltage to supply the rated voltage to each device of the second device 150. The DC / DC converter has a high efficiency of more than 90% and has a problem in that a large component such as an inductor, a transformer, and a capacitor is embedded and takes up a lot of space on a circuit board. Accordingly, when using a DC / DC converter a lot, it is difficult to manufacture a small portable device.

Here, a voltage supply device of a general portable device will be described in detail with reference to FIG. 2.

When the plurality of LDO regulators of the first voltage converter 120 shown in FIG. 1 are inputted from the battery which is the voltage source 100 through the power rail 105, the DC voltage “4.2 to 3.0 V” is input, the input DC voltage is input. Convert "4.2 to 3.0V" into preset DC voltages such as "3.3V", "2.8V", and "2.5V". The plurality of LDO regulators step down the input DC voltage to a predetermined voltage and output the output voltage. In this case, the input voltage may be generated at least 0.2 to 0.3 V higher than the output voltage to generate the preset output voltage. The minimum difference between 0.2 and 0.3V between the input voltage and the output voltage is referred to as a drop out voltage. Here, for the purpose of explanation, it is assumed that the minimum voltage difference between the input voltage and the output voltage of the LDO regulator is "0.3V". Therefore, since the first voltage converter 120 should output a maximum voltage of "3.3V", the minimum input voltage should be "3.6V".

In addition, when a plurality of DC / DC converters of the second voltage converter 130 are inputted from the battery which is the voltage source 100 through the power rail 105, the DC voltage “4.2 to 3.0V” is input. Convert 4.2 to 3.0V "into preset DC voltages such as" 1.8V "and" 1.5V ". The plurality of DC / DC converters boost or step down the input DC voltage to output a preset voltage.

On the other hand, the battery supplies a voltage of "4.2 ~ 3.0V" to the first voltage converter 120 composed of a plurality of LDO regulators, the predetermined LDO regulator of the first voltage converter 120 is "4.2 ~ 3.6 Only voltage up to V " is supplied to output a voltage of " 3.3 V ", and a voltage lower than " 3.3 " That is, as shown in FIG. 2, the LDO regulator generating an output voltage of "3.3V" is "3.3V" when the input voltage becomes "3.6V" or less when the "3.6V" is cut-off. The output voltage of V "will not be generated, which may lead to system power off depending on the design of the portable device.

As a result, the first voltage converter 120 may not properly use the remaining power “3.6 to 3.0 V” after the battery power is consumed by 80% or more.

3 is a view showing an example of a voltage supply device of a portable device according to the present invention, Figure 4 is a graph showing the power consumption as an example in FIG.

Referring to FIG. 3, a voltage supply device of a portable device includes a voltage compensator 310, a first voltage converter 320, and a second voltage converter 330. The first voltage converter 320 receives DC power output from the voltage supply source 300 through the power rail 305, and the second voltage converter 330 is output from the voltage compensator 310. DC power is input through the power rail 325.

The voltage source 300 is a battery storing DC power, and outputs DC power stored therein, and may be used for single use or alternately charging and discharging.

Here, in the future, there are various types of batteries of the mobile phone device, but for the purpose of explanation, the battery provided in the mobile phone will be described as an example. In addition, although the DC power is received from the battery in the above, it is preferable that the DC power may be received from the outside.

The voltage compensator 310 is positioned between the voltage source 300 and the first voltage converter 320, and presets the voltage of the DC power input when DC power is input from the voltage source 300. It converts to a certain level of voltage and outputs stable DC power.

The voltage compensator 310 is a DC / DC converter for boosting or stepping down the input voltage to a preset voltage. In addition, the voltage output from the voltage compensator 310 is a rated output voltage of a predetermined LDO regulator that outputs the highest voltage among a plurality of LDO regulators of the first voltage converter 320, and a dropout of the predetermined LDO. Out) is determined by summing the voltages.

The first voltage converter 320 receives a DC power output from the voltage compensator 310 to step down a voltage of the DC power to supply a rated voltage to each device of the first device 340. to be.

The second voltage converter 330 is a plurality of DC / DC converters for supplying a rated voltage to each device of the second device 350 by stepping up or down the voltage of the DC power input from the voltage supply source 300.

As a result, a power rail 315 for the first voltage converter 320 is formed through the voltage compensator 310 so that the first voltage converter 320 receives the voltage from the voltage compensator 310. The rated voltage may be supplied to the second device 350 by converting the received voltage.

Here, the voltage supply device of the portable device according to the present invention will be described in detail with reference to FIG. 4.

In the plurality of DC / DC converters of the second voltage converter 310 illustrated in FIG. 3, when a DC voltage “4.2 to 3.0 V” is input through the power rail 305 from the battery that is the voltage supply source 300, the input voltage is input. The DC voltage "4.2 to 3.0V" is converted into a predetermined DC voltage such as "1.8V" and "1.5V". The plurality of DC / DC converters boost or step down the input DC voltage to output a preset voltage.

In addition, when the DC / DC converter of the voltage compensator 310 inputs the DC voltage “4.2 to 3.0V” from the battery which is the voltage source 300 through the power rail 305, the input DC voltage “4.2 to 3.0V” is input. Is stepped up or down to output a preset DC voltage "3.6V". Here, the preset DC voltage "3.6V" is a drop of the output voltage "3.3V" of the predetermined LDO regulator that outputs the highest voltage in the plurality of LDO regulators of the first voltage converter 320 below and the predetermined LDO regulator. This is the sum of Drop Out voltage "0.3V".

In addition, the first voltage converter 320 receives the DC voltage "3.6V" output from the voltage compensator 310 through the power rail 325, and receives "3.3V", "2.8V", and "2.5V". Change to a preset DC voltage such as "

As a result, the voltage supply device of the present invention can efficiently use a DC voltage up to "3.6 ~ 3.0V" output from the battery through the voltage compensation unit 310. As described above, the plurality of LDO regulators of the first voltage converter 320 generates an output voltage preset as the input voltage when the input voltage is at least "0.3V" higher than the output voltage. The "0.3V" is referred to as a drop out voltage.

Accordingly, the LDO regulator outputting a DC voltage of "3.3V" should receive a DC voltage of at least "3.6V", and receives a DC voltage of "3.6V" through the voltage compensator 310. That is, the voltage compensator 310 receives a DC voltage of "4.2 ~ 3.0V" from the battery and always outputs a DC voltage of "3.6V" and supplies it to the plurality of LDO regulators of the first voltage converter 320. As a result, the plurality of LDO regulators generate a preset output voltage.

As a result, the first voltage converter 320 including the plurality of LDO regulators may operate normally even when “3.6 to 3.0 V” is output while the battery consumes 80% or more of the power.

5A illustrates an example of the power efficiency in FIG. 1, and FIG. 5B illustrates an example of the power efficiency in FIG. 3.

5A and 5B, the power efficiency of the voltage supply device according to the present invention will be described in comparison with the power efficiency of a general voltage supply device.

5A and 5B are calculated by considering the efficiency of the DC / DC converter as 95% and the efficiency of the LDO regulator as an output voltage / input voltage ratio.

As shown in FIG. 1, a power supply of a voltage supply device of a general portable device includes a first voltage converter 130 including a plurality of LDO regulators and a second voltage converter 110 including a plurality of DC / DC converters. The loss is "402mW" with reference to FIG. 5A. In detail, when the second voltage converter 130 receives DC power from the battery, which is the voltage source 100, and supplies power to each device 150, the power loss is “31 mW,” and the first voltage converter In 120, the power loss is “332mW” in receiving DC power from the battery, which is the voltage source 100, and supplying power to each device 140.

In addition, as shown in FIG. 3, the voltage compensator 310, which is a DC / DC converter, the first voltage converter 320 formed of a plurality of LDO regulators, and the second voltage converter configured of a plurality of DC / DC converters. The power loss of the voltage supply device of the portable apparatus according to the present invention consisting of 330 is "394mW" when referring to FIG. 5B. In detail, when the second voltage converter 330 receives DC power from the battery, which is the voltage source 300, and supplies power to each device 350, the power loss is “31 mW” and the voltage compensator 310 ), When the DC power is input from the battery, which is the voltage source 300, to supply the predetermined voltage for driving the first voltage converter 320 to the first voltage converter 320, the power loss is "67mW." . In addition, when the first voltage converter 320 receives DC power from the voltage compensator 310 and supplies power to each device 140, the power loss is “296 mW”.

Comparing the power loss, it can be seen that the loss of the voltage supply device of the portable device according to the present invention is "296mW". This is possible through the voltage compensator 310. As the number of LDO regulators increases, power loss is reduced, thereby enabling a power supply device having high power efficiency.

After all, the main feature of the present invention is to increase the power efficiency by efficiently using the remaining capacity through the voltage compensator 310 even when the remaining power (capacity) of the battery is about 20%. The voltage compensator 310 boosts or steps down the DC voltage of the DC power inputted to the DC / DC converter to output a preset DC voltage, and accordingly, the plurality of LDO regulators of the first voltage converter 320 This is because DC power is received from the voltage compensator 310 to supply DC power to each device 340.

On the other hand, the portable device can be applied to not only the specific mobile phone described above, but also to a portable camera, a communication terminal, and the like, and the present invention is not limited thereto, and it can be easily understood by those skilled in the art.

That is, while the present invention has been illustrated and described with reference to certain preferred embodiments, those of ordinary skill in the art may vary within the scope of the present invention without departing from the scope of the present invention. It can be easily seen that it can be modified and changed. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

As described in detail above, according to the present invention, the first voltage converter needs a voltage of the DC power input from the voltage compensator in each device as a stable voltage is provided to the first voltage converter with a voltage compensator. Convert it to the rated voltage and supply the converted rated voltage to the device concerned.

That is, the voltage input through the voltage compensator, which is a DC / DC converter, is stepped down or stepped up to supply a constant voltage to the first voltage converter so that the first voltage converter, which is an LDO regulator, can output the rated voltage of the device.

Therefore, the LDO regulator for outputting the set voltage when the input voltage is greater than a predetermined value can be operated even if there is little remaining capacity in the battery. As a result, the battery life can be extended by making the best use of the low capacity battery.

Claims (7)

A voltage compensator for converting a voltage applied from a voltage source into a voltage of a predetermined level and outputting the converted voltage; And And a first voltage converter converting a voltage of a predetermined level output by the voltage compensator to supply a rated voltage to a first device. The method of claim 1, And a second voltage converting unit converting a voltage input from the voltage supply source and supplying a rated voltage to a second device. The method according to claim 1 or 2, The voltage supply device of a portable device, characterized in that the battery. The method of claim 2, And the second voltage converter comprises at least one DC / DC converter. The method of claim 1, And the voltage compensator is a DC / DC converter. The method of claim 1, The first voltage converter includes at least one low drop output (LDO) regulator, characterized in that the voltage supply device of a portable device. The method of claim 6, The voltage of a predetermined level output by the voltage compensator The voltage supply device of a portable device, characterized in that the sum of the output voltage of the LDO regulator that outputs the highest of the at least one or more LDO regulator and the Drop Out voltage generated in the LDO.

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