CN103259328A - Continuous direct current power supply system - Google Patents

Abstract

The invention provides an uninterrupted DC power supply system. The power input and enabling terminal of the No. 1 power supply chip are connected to 5V, the ground terminal is directly grounded, and the output pin is connected to two parallel capacitors C1, C2 and the Schmitt trigger. At the input terminal, the voltage positive pole of the Schmitt trigger is connected to 5V, and the ground terminal is grounded. The output terminal of the Schmitt trigger is connected to the enable terminal of the No. 2 power chip. The input voltage of the No. 2 power chip is 5V, and the output terminal One end of the capacitor C3 is connected, and the other end of the capacitor C3 is grounded; the output ends of the No. 1 power chip and the No. 2 power chip are respectively connected together through a non-reverse diode to output a voltage of 3V. The invention can provide uninterrupted power supply when the No. 1 power chip fails, and simultaneously start the work of the No. 2 power chip. The circuit has few components, low cost, light weight and low power consumption, which increases the reliability and stability of the power supply system and broadens the application environment of the design system.

Description

Uninterruptible DC Power Supply System

technical field

The invention relates to a design scheme of a continuous power supply system based on a dual power supply chip failure conversion process.

Background technique

DC voltage continuous power supply is mainly used to power smart chips, such as FPGA, ARM, DSP and other chips that require low current and low energy consumption, because once the power supply fails or the circuit is disconnected, these chips need to reload the program when they are powered on again , Even the peripheral devices of these chips need to be restarted, which not only wastes time, but also increases energy consumption. At present, the continuous power supply system of dual power supplies is relatively complicated when a power supply chip fails, and some system designs use more chips, resulting in an increase in cost. The increased weight of the design circuit poses a greater problem for fields such as aerospace. At the same time, the more chips used, the greater the probability of failure. Therefore, it is necessary to use less chips, the entire power supply system is lightweight, simple in structure, and highly reliable to ensure the reliability and continuity of power supply.

Contents of the invention

In order to overcome the deficiencies of the prior art, the present invention provides an uninterrupted direct current power supply system with low energy consumption and small usage of chips.

The technical solution adopted by the present invention to solve its technical problems is: comprising two power supply chips, two diodes, a Schmitt trigger and three capacitors, the power input and enable terminal of the No. 1 power supply chip are connected to 5V, and the ground Directly grounded, the output pin is connected to two parallel capacitors C1, C2 and the input terminal of the Schmitt trigger, the positive voltage of the Schmitt trigger is connected to 5V voltage, and the ground terminal is grounded, at the output terminal of the Schmitt trigger Connect to the enable end of the No. 2 power chip, the input voltage of the No. 2 power chip is 5V, the output end is connected to one end of the capacitor C3, and the other end of the capacitor C3 is grounded; the output ends of the No. 1 power chip and the No. The diodes are connected together and the output voltage is 3V.

The power supply chip adopts two LDO power supply chips of TI Company.

The threshold voltage of the Schmitt trigger is 1.6-2.4V.

Said diodes are all Schottky diodes, and the threshold voltage is 0.2-0.3V.

其中，ω为系数，ω>1，ｔ为放电时间，ｔ值等于施密特触发器触发时间与二号电源芯片的启动时间之和；Ｒ为电源所供电系统的折合的电阻值，Ｖ_ｔ电为供电系统所能接受的最小电压值；Ｅ为施密特触发器V_T-的电压值。The capacitance value of the capacitor C1

Among them, ω is the coefficient, ω>1, t is the discharge time, and the t value is equal to the sum of the trigger time of the Schmitt trigger and the start-up time of the second power chip; R is the converted resistance value of the power supply system of the power supply, V _t Electricity is the minimum voltage value that the power supply system can accept; E is the voltage value of Schmitt trigger V _T- .

The capacitors C2 and C3 are 10pF capacitors.

The beneficial effects of the present invention are: the present invention does not use intelligent detection devices for control, and can start the work of the second power chip while supplying uninterrupted power when the first power chip fails. This circuit system design utilizes fewer components, low cost, light weight, and low power consumption, which can increase the reliability and stability of the power supply system and broaden the application environment of the design system, even in the aerospace field.

Description of drawings

Fig. 1 is a schematic circuit diagram of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The design scheme of the present invention adopts two LDO power supply chips of TI Company, the input voltage is 5V, and the output voltage is 3V. The input voltage of the Schmitt trigger is 5V, and the threshold voltage is 1.6-2.4V. The two diodes in the circuit are Schottky diodes (germanium diodes, the threshold voltage is 0.2-0.3V). C1 is a large capacitor, and its capacitance value is calculated as shown in formula 1, and its main function is to store electric energy. C2 and C3 usually use 10pF capacitors, the main function is filtering.

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&omega;t</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}{\mathrm{<span\; class="notranslate">\; E.</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them; ω is the coefficient, ω>1; C is the capacitance value of the capacitor C1; t is the discharge time, and the t value is equal to the sum of the trigger time of the Schmitt trigger and the start-up time of the power supply 2 chip; R is the power supply system of the power supply The converted resistance value is estimated by power consumption; V _t is the minimum voltage value that the power supply system can accept; E is the voltage value of Schmitt trigger V _T- .

Design scheme: connect the power input and enable terminal of power chip 1 to 5V, and connect the ground terminal to ground directly. The output pin of the power supply chip 1 is connected with two capacitors C1 and C2 connected in parallel, and connected with the input terminal of the Schmitt trigger at the same time. The enable end of the chip 2 is directly powered at the output end of the Schmitt trigger. The input voltage of chip 2 is 5V, the output terminal is connected to one end of capacitor C3, and the other end is grounded. At the same time, a diode is connected to the output terminals of the power chip 1 and the power chip 2, and they are connected together to output a 3V voltage.

When powering on, the power input pin and enable pin of chip 1 input 5V voltage, and chip 2 input 5V voltage. When the voltage output terminal is higher than the threshold voltage of D1 by 0.2-0.3V, the power supply system will output voltage, and when C1 and C2 are fully charged, the output voltage will be output normally. Once the chip 1 fails, the chip 1 will stop working. At this time, the capacitor C1 starts to discharge, and the voltage shows a downward trend. When the voltage at point a is lower than the V _T- of the Schmitt trigger, the Schmitt trigger The special trigger will flip, and the voltage at point b will become a high level, making the enable terminal of chip 2 enter and exit high voltage, then chip 2 will start power supply, when the output voltage is higher than the threshold voltage of D2 , the whole power supply system will work normally. The chip 2 starts up before the capacitor C1 is discharged to 0.3V, and the voltage rises to 0.3V, so that the continuity of the power supply system can be guaranteed. Once chip 1 is not completely damaged and resumes normal operation, the Schmitt trigger will not reverse when the output of chip 1 does not reach the V _T+ of the Schmitt trigger. As the voltage rises to V _T+ At this time, the enable terminal of chip 2 will become low level, causing chip 2 to stop working. At this time, the entire power supply system has a normal output voltage of 3V. In this way, the power supply of the power supply system is continuous and uninterrupted during the power conversion process.

Referring to Figure 1, the uninterrupted DC power supply system implemented in this implementation uses 2 single-channel LDO chips from TI Company with an input of 5V, an output of 3V, and an enable terminal of 3-5V. The V _T+ of the Schmitt trigger is 2.4V, V _T- is 1.6V, Vin is 5V, the output high voltage of OUT is about 4.4V, and the reversal time is 15ns. Capacitor C1 is a 10mF capacitor. Its main function is to store electricity to prevent chip 1 from being damaged and stop power supply, and to provide emergency power supply capabilities. Capacitors C2 and C3 are mainly used for filtering. Diodes D1 and D2 use Schottky diodes, the threshold voltage is 0.2-0.3V, and the main function is to use the unidirectional conduction characteristics of the diodes. Under normal conditions of chip 1, the voltage at point a is greater than V _T+ , so the output of the OUT terminal of the Schmitt trigger is low level, and the enable terminal EN of chip 2 is low level.

When chip 1 is working normally, C1 is in a fully charged state for emergency use in case of power failure. At this point, the voltage at point a is 3V. Once chip 1 fails and stops power supply, C1 will start to discharge and show a downward trend of supply voltage. When the voltage drops to V _T- voltage 1.6V, the voltage at point a is 1.6V, and then a Schmitt trigger will occur Inversion, the voltage drop at point b changes from low level to high level, and chip 2 starts. When the voltage of chip 2 is higher than the threshold voltage of D2, the voltage at point c rises and reaches a voltage of 3V.

The time for the entire capacitor C1 to discharge from 1.6V to the lowest voltage range that the power-demanding system can withstand must be greater than the time it takes for the chip 2 to start normally.

Once the chip 1 resumes normal operation, the capacitor C1 will continue to charge until the voltage at point a is higher than 2.4V, the Schmitt trigger flips, and the chip 2 stops supplying power. The voltage at point c always maintains a continuous and uninterrupted power supply.

Apparently, the above examples are only examples for clearly illustrating the present invention, rather than limiting the embodiment of the present invention. For those of ordinary skill in the art, various changes can be made on the basis of the above description. For example, the voltage of the Schmitt trigger is not the required voltage, and the voltage can be divided by connecting resistors in series at point a; increasing the capacitor C1 to increase the lowest point voltage of power conversion and other designs. It cannot be exhaustive here, but the obvious changes or changes derived from the spirit of the present invention are still within the scope of protection.

Claims (6)

1. uninterrupted direct current (DC) power supply system, comprise two power supply chips, two diodes, a Schmidt trigger and three electric capacity, it is characterized in that: termination 5V is imported and enabled to the power supply of a power supply chip, the direct ground connection of earth terminal, output pin connects the capacitor C 1 of 2 parallel connections, the input of C2 and Schmidt trigger, the positive polarity of Schmidt trigger connects 5V voltage, earth terminal ground connection, Enable Pin at No. two power supply chips of output termination of Schmidt trigger, the input voltage of No. two power supply chips is 5V, output termination capacitor C 3 one ends, capacitor C 3 other end ground connection; The output of a power supply chip and No. two power supply chips is connected together by a non-return diode respectively, output 3V voltage.

2. uninterrupted direct current (DC) power supply system according to claim 1 is characterized in that: the LDO power supply chip of 2 TI companies of described power supply chip employing.

3. uninterrupted direct current (DC) power supply system according to claim 1, it is characterized in that: the threshold voltage of described Schmidt trigger is 1.6～2.4V.

4. uninterrupted direct current (DC) power supply system according to claim 1, it is characterized in that: described diode is Schottky diode, and threshold voltage is 0.2～0.3V.

5. uninterrupted direct current (DC) power supply system according to claim 1 is characterized in that: the capacitance of described capacitor C 1

Wherein, ω is coefficient, ω〉1, t is discharge time, the t value equals sum start-up time of Schmidt trigger triggered time and No. two power supply chips; R is the resistance value of amounting to of power supply institute electric power system, V _TElectricity is the receptible minimum voltage value of electric power system; E is Schmidt trigger V _T-Magnitude of voltage.

6. uninterrupted direct current (DC) power supply system according to claim 1, it is characterized in that: described capacitor C 2 and capacitor C 3 are selected the electric capacity of 10pF for use.

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