TW529216B - Circuit for preventing backflow of reverse current and having battery voltage detection - Google Patents

Abstract

A kind of circuit for preventing backflow of reverse current and having battery voltage detection to stabilize system voltage is disclosed in the present invention. The invention at least contains a voltage regulator for providing stable voltage for the system, and a voltage detection unit for providing battery power detection. As the battery power is higher than a level, the voltage regulator provides a stable power for the system and the voltage regulator charges the capacitor as a spare electric power when the battery power is insufficient. As the battery power is lower than a level, the voltage detection unit provides a signal for the system to enter a power saving mode. And, the backflow prevention switch is closed to prevent backflow of the spare electric power of the capacitor to the voltage regulator. Thus, the spare electric power stored in the capacitor is capable of providing spare electric power for the system to take the corresponding strategy such as conducting data storage and turning off system, or replacing another battery, or connecting AC power source.

Description

529216 V. Description of the invention (1) Field of the invention: The present invention discloses an electronic detection circuit, and more particularly, it relates to a circuit with electric rabbit voltage detection and reverse current reverse current prevention circuit, so that the system will be under standby power immediately. Responsive circuit design is adopted to protect the system from data corruption. Background of the Invention: One use of portable electronic consumer products is to use an AC power source indoors, and to use a rectifier carried with them to provide its operating voltage. However, to emphasize its portability, the most common way is to use the random battery that is basically provided with this portable electronic consumer product to provide its power. However, the common portable electronic consumer products, when the voltage is lower than the predetermined value, if the battery is not immediately switched off and replaced, the system will be unstable. At this time, if not processed in real time, the data may be lost and the user may be troubled. For example, laptops, personal digital assistants, PDAs, and other electronic products. Although, most notebook computers, personal digital assistants, PDAs, or electronic dictionaries on the market have battery power detection devices. When the battery power detection devices detect insufficient power, they will issue a warning tone to notify users to shut down. And storage. However, the above-mentioned battery power detection devices are all one-way detection, and will only operate when there is a power supply. When the battery power is above a level, the battery power detection device does not produce any effect. And when the battery power is lower than one

529216 5. Description of the invention (2) On time, the battery power detection device provides a signal to the system to issue a warning sound. However, the above-mentioned battery power detection device relies on the battery to provide power. If the battery power drops too quickly to a certain water level, the battery power detection device will have no effect, thus causing system instability. In view of this, the present invention will therefore provide a circuit design to improve the above problems. Purpose and summary of the invention:

The purpose of the present invention is to provide a voltage stabilization and battery voltage detection protection circuit for providing a stable voltage for portable electronic products using batteries. The battery voltage detection and reverse current backflow prevention circuit disclosed in the present invention can be used to provide a stable voltage for the system using the battery, and when the battery power is insufficient, provide the system's backup power immediately to take the corresponding circuit design. .

The circuit of the present invention includes at least: a voltage regulator to provide a stable voltage of the system; a voltage detection unit to provide battery power detection; when the battery power is higher than one level, the voltage regulator provides stable power to the system At the same time, the voltage regulator charges the capacitor as backup power when the battery power is insufficient. When the battery power is lower than one bit, the voltage detection unit provides a signal to the system to enter the power saving mode. At the same time, the reverse current prevents the switch from closing to prevent the backup power of the capacitor from flowing back to the voltage regulator. At this time, the capacitor stores

Page 5 529216 V. Description of the invention (3) The backup power will provide system backup power at this time to take countermeasures, such as storing data and shutting down the system. Or replace it with another battery, or connect AC power supply. Detailed description of the invention: FIG. 1 is a voltage stabilization and battery voltage detection protection circuit designed according to an embodiment of the present invention, which is used to provide a stable voltage for a system using a battery, and to provide the system backup immediately when the battery power is insufficient. Electricity in order to take countermeasures to the circuit design. It includes a voltage detection unit 100, a reverse current preventing switch Q1, a capacitor C1, and a low-loss voltage regulator (10w-dr0pped 0ut voltage regulator) LD0 ic. The above system is a portable electronic product, which can store data or process data, such as pDA, a computer dictionary or a pen-shaped electronic monthly bag, etc., or a pDA mobile phone that also has the function of transmitting data. And the above circuit components, unless otherwise specified, are supplied by the same battery. Among them, the backflow prevention switch Q 1 grand ^ ^ ^ ^] is a integrated circuit with a cheek-like pMOS transistor function. When the backflow prevention switch is used, QR & — When the input voltage level of the gate G of the gate ΊΊ is 丨 丨 0 '丨, as shown in the figure, LD 0 I Γ white ^ mountain ^ 1L output terminal OUT output current to the reverse current prevention switch Source S of Q 1. Let the lightning be μ 丄 0. &Amp; _ _ _ _ _ _ _ from the fast machine through the drain D to the capacitor C1 in series with the source S for charging. When the capacitors are charged to a capacitor saturation voltage, a stable voltage is provided through the VCC terminal to the capacitor A A, ^ ^ ^ main system. In addition, the back-flow prevention switch Q1 has a lower impedance than the normal gold chlorobenzene μ / rabbit milk cow wide crystal (M0S) when it is turned on. but

529216 V. Description of the invention (4) When the input voltage level of the gate G of Q1 is "1", the back-flow prevention switch Q1 is closed, and relatively has a higher impedance than a single M0s transistor. In other words, the backflow prevention switch Q1 is a one-way conduction integrated circuit. The voltage detection unit 100 includes a second resistor r2, a bipolar transistor Q2, a first resistor, and a voltage detector IC 1 1 0 ° The second resistor R2 is connected across The source s and the gate G of the backflow prevention switch Q 丨. The voltage detection IC 1 1 〇 is used to detect whether the battery power is still higher than the reference. If the battery connected to the BAT terminal of the voltage detection IC 1 1 〇, the voltage is sufficient when the battery is' voltage detection IC 1 1 0 V fai 1 output is the voltage level, '1', $ sign. At this time, 'the bipolar transistor Q2 is simultaneously powered by a battery connected to the BAT terminal', and the transistor B is turned on from the base B via the bias resistor R1. Because f 'transistor Q2's set extreme bat-fail is maintained at the voltage level, 0 ". Yu 疋 = According to the above uo I c continues to provide a stable voltage via the vcc terminal to the system, please note that the LDO IC is provided by the battery from βΑΤ Electricity. In another case, 'if the battery power connected to the BAT terminal of the voltage detection IC 11 0 is lower than the λ 疋 level, or when the battery is unplugged, the Vfail output of the voltage detection α 110 changes from high to low The signal of transistor Q2 will be turned off (0FF). And the voltage of the transistor 经由 ^ ^ Π ^ t ^ ^ t ^ Cl voltage (VCC). On this day, rat FATT, s -V, L7 -^ Φ ^ 夺 ΒΑΤ a FAIL notification system to enter the most power-saving mode; r temporary: Thunder: Guang t t The power stored by the capacitor C1 is lifted through the VCC terminal, a short-term fertilizer. At this time, it is prevented from turning on due to the reverse current. Exists and is

529216 V. Description of the invention (5) In the closed state (gate G is at the voltage level "lff), therefore, the electric energy of the capacitor will not flow back to the LD IC. However, when the battery power is lower than the set level, or the battery is Before unplugging the power, the length of time that capacitor C1 supplies power to the system depends on the size of capacitor C1. The system can use the capacitor C1 to supply power to the system and take countermeasures such as data storage, and then The system shuts down. Or replace another battery, or connect AC power supply, etc. Advantages of the invention: The invention can provide stable voltage for portable electronic products, and even when the battery power is insufficient, it can provide enough time to respond, so Free from damage to the data. The above description is only the preferred embodiments of the present invention, and is not intended to limit the scope of patent application of the present invention; any other equivalent changes or modifications made without departing from the spirit disclosed by the present invention , Should be included in the scope of patent application below.

529216 The diagram briefly illustrates the preferred embodiment of the present invention and will be explained in more detail in the following explanatory text with the following figures: Figure 1 shows the voltage stabilization and battery voltage detection protection circuit of the present invention for providing use The battery system has a stable voltage, and when the battery power is insufficient, it can provide backup power of the system immediately to take corresponding circuit design. Drawing number comparison table:

Voltage detection unit 100 Backflow prevention switch Q1 Low-loss voltage regulator LDO I C Voltage detection I C 110 BAT Battery supply terminal Capacitor C1

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Claims (1)

529216 6. Scope of patent application 1. A battery voltage detection and reverse current reverse current prevention circuit is provided to provide a stable voltage for the system using the battery, and when the battery power is insufficient, the system's backup power is immediately provided to take the response The circuit design of the measure includes at least: a voltage regulator provided by the battery to provide a stable voltage of the system; a voltage detection unit provided by the battery to provide battery power detection, and when the When the battery power is insufficient, a signal is provided to the system to enter the power saving mode; a capacitor is connected to the backflow prevention switch to provide the system's backup power; and a backflow prevention switch is connected to the output of the voltage regulator and Between the output terminals of the voltage detection unit is used to prevent the backup power of the capacitor from flowing back to the voltage regulator when the battery power is insufficient. 2. The circuit of item 1 in the scope of patent application, wherein the above voltage detection unit includes at least a first resistor, a transistor, a second resistor and a voltage detection IC, wherein the second resistor is connected to the counter current The gate and source of the switch are prevented. The emitter of the transistor is grounded. The collector is connected to the gate of the backflow prevention switch. The base is connected to an output terminal of the voltage detection IC. The second resistor is used as The bias resistor is powered by the battery. 3. The circuit of item 1 in the scope of patent application, wherein the above-mentioned reverse current prevention switch is a P-type transistor. 529216 6. Scope of patent application 4 · If the circuit of the first scope of the patent application, the two plates of the capacitor are connected between the source of the reverse current prevention switch and the ground reference potential. 5. The circuit according to item 1 of the scope of patent application, wherein the above system is an electronic product using the above battery as power. Page 11