CN214281235U - 5V-3.3VLDO circuit - Google Patents
5V-3.3VLDO circuit Download PDFInfo
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- CN214281235U CN214281235U CN202022887166.3U CN202022887166U CN214281235U CN 214281235 U CN214281235 U CN 214281235U CN 202022887166 U CN202022887166 U CN 202022887166U CN 214281235 U CN214281235 U CN 214281235U
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Abstract
The utility model discloses a LDO circuit, equipment power supply conversion field. A5V-3.3V LDO circuit comprises a power input end VCC-5V-COM, an IC conversion chip and a power output end VCC-3V 3, wherein the IC conversion chip comprises a power input pin VIN, a feedback pin VFB, a grounding pin GND, a switch power output pin SW and a starting pin RUN. The utility model discloses compare in DC power supply converting circuit output little, circuit structure is simple, the ripple coefficient is little, efficient, the noise is low.
Description
Technical Field
The utility model relates to an equipment power supply conversion field especially relates to a low dropout linear regulator (LDO) circuit, and specifically speaking relates to a 5V changes 3.3V LDO circuit.
Background
With the rapid development of information science, the functions of portable electronic devices are increasingly powerful and the degree of integration is rapidly improved, so that attention is paid to how to provide stable and efficient power supply for the electronic devices, and the power supply IC technology is also increasingly important. Among the power technologies, low dropout linear regulator (LDO) technology has gradually increased its share in the market due to its small size and low noise.
A Low-dropout regulator (LDO), also called a Low-dropout linear regulator and a Low-dropout regulator, is one of linear dc voltage regulators, and is used to provide a stable dc voltage power supply. Compared with a common linear direct current voltage regulator, the low dropout voltage regulator can work under the condition of smaller output and input voltage difference. The LDO load commonly used at present cannot be too large, and the efficiency is low.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an LDO circuit can more stably, more efficient carry out DC power supply's step-down conversion.
The technical scheme provided by the utility model as follows:
A5V-3.3V LDO circuit comprises a power input end VCC-5V-COM, an IC conversion chip and a power output end VCC-3V 3, wherein the IC conversion chip comprises a power input pin VIN, a feedback pin VFB, a ground pin GND, a switch power output pin SW and a start pin RUN; the power input end VCC _5V _ COM is connected with one end of a magnetic bead L19, the other end of the magnetic bead L19 is connected with one end of a parallel capacitor consisting of a capacitor C92 and a capacitor C163, and is connected with a VIN pin and an RUN pin of the IC conversion chip, and the other end of the parallel capacitor is grounded;
the SW pin is connected with one end of an inductor L20, the other end of the inductor L20 is connected with one end of a capacitor C168, one end of a resistor R47 and one end of a parallel capacitor formed by the capacitor C165, the capacitor C166 and the capacitor C167, then the power output end VCC _3V3 is connected, the other end of the parallel capacitor is grounded, and the capacitor C168 is connected in parallel with two ends of a resistor R47;
the VFB pin is connected to the other end of the capacitor C168, the other end of the resistor R47, and one end of the resistor R52, and the other end of the resistor R52 is grounded.
In a further technical scheme, the IC chip selects SY8008BAAC, and conversion of the step-down direct-current power supply for input and output of the circuit is achieved.
In the further technical scheme, the output power of the 3.3V power supply output interface is relatively small, and the output voltage is VCC=VFB(1+ R47/R52). Changing the resistance values of R47 and R52 can change the output voltage.
The utility model discloses an inductance L19 selects magnetic BEAD BEAD, compares in the inductance, and the series connection of magnetic BEAD equivalent resistance and inductance has very high resistivity and magnetic permeability, has better high frequency filtering characteristic to be favorable to suppressing the high frequency noise on the power cord than ordinary inductance.
Advantageous effects
Compared with the prior art, the utility model has the advantages of it is as follows showing:
compare in DC power supply converting circuit, the utility model discloses a LDO circuit simple structure, power loss is little, and stability is good, and load response is fast, and the ripple coefficient is little, can obtain extensive application in some low pressure power supply electronic equipment.
Drawings
FIG. 1 is a schematic diagram of a 5V to 3.3V LDO circuit.
Detailed Description
In order to further understand the operation of the circuit of the present invention, the present invention will be further described in detail with reference to the accompanying drawings.
As shown in fig. 1, a 5V-3.3V LDO circuit includes a power input terminal VCC _5V _ COM, an IC conversion chip and a power output terminal VCC _3V3, where the IC conversion chip includes a power input pin VIN, a feedback pin VFB, a ground pin GND, a switching power output pin SW and a start pin RUN; the power input end VCC _5V _ COM is connected with one end of a magnetic bead L19, the other end of the magnetic bead L19 is connected with one end of a parallel capacitor consisting of a capacitor C92 and a capacitor C163, and is connected with a VIN pin and an RUN pin of the IC conversion chip, and the other end of the parallel capacitor is grounded; the parallel capacitors are used for filtering, the large capacitor C163 is a capacitor for filtering low frequency, and the small capacitor C92 is a capacitor for filtering low frequency.
The SW pin is connected with one end of an inductor L20, the other end of the inductor L20 is connected with one end of a capacitor C168, one end of a resistor R47 and one end of a parallel capacitor formed by the capacitor C165, the capacitor C166 and the capacitor C167, then the power output end VCC _3V3 is connected, the other end of the parallel capacitor is grounded, and the capacitor C168 is connected in parallel with two ends of a resistor R47;
the VFB pin is connected to the other end of the capacitor C168, the other end of the resistor R47, and one end of the resistor R52, and the other end of the resistor R52 is grounded.
The capacitor C168 is connected in parallel at two ends of the resistor R47, and the capacitor C168 has the feed-forward effect, so that the phase margin is improved, and the corresponding speed of the power supply is increased.
The output power of the 3.3V power supply output interface is relatively small, and the output voltage is VCC=VFB(1+ R47/R52). Changing the resistance values of R47 and R52 can change the output voltage.
The IC conversion chip selection SY8008BAAC comprises a power input pin VIN, a feedback pin VFB, a ground pin GND, a switching power output pin SW and a starting pin RUN; the power input end is respectively connected with a VIN pin and an RUN pin, the SW pin is connected with an inductor and a capacitor and is grounded, the VFB pin is connected with a divider resistor and is connected with an output power end, and the conversion of the step-down direct-current power supply for circuit input and output is realized.
Specifically, the power input terminal is connected with the VIN pin, voltage is input to the chip, and the RUN pin is connected to enable the chip to start working. The SW pin is connected with one end of an inductor L20, the other end of the SW pin is connected with an output power supply, and is also connected with a parallel circuit consisting of a capacitor C165, a capacitor C166 and a capacitor C167 and is grounded, so that the functions of voltage stabilization and filtering are realized. The VFB pin is a feedback end of feedback voltage, is connected with output voltage through a resistor, and adjusts the output voltage through the output ratio of an external resistor, namely the VFB pin is connected with one end of a resistor R47 and one end of a resistor R52, the other end of the resistor R52 is grounded, the other end of the resistor R47 is connected with an output power supply end, and the resistors R47 and R52 are voltage dividing resistors.
Claims (3)
1. A5V-3.3V LDO circuit comprises a power input end VCC-5V-COM, an IC conversion chip and a power output end VCC-3V 3, wherein the IC conversion chip comprises a power input pin VIN, a feedback pin VFB, a ground pin GND, a switch power output pin SW and a start pin RUN; the power input end VCC _5V _ COM is connected with one end of a magnetic bead L19, the other end of the magnetic bead L19 is connected with one end of a parallel capacitor consisting of a capacitor C92 and a capacitor C163, and is connected with a VIN pin and an RUN pin of the IC conversion chip, and the other end of the parallel capacitor is grounded;
the SW pin is connected with one end of an inductor L20, the other end of the inductor L20 is connected with one end of a capacitor C168, one end of a resistor R47 and one end of a parallel capacitor formed by the capacitor C165, the capacitor C166 and the capacitor C167, then the power output end VCC _3V3 is connected, the other end of the parallel capacitor is grounded, and the capacitor C168 is connected in parallel with two ends of a resistor R47;
the VFB pin is connected to the other end of the capacitor C168, the other end of the resistor R47, and one end of the resistor R52, and the other end of the resistor R52 is grounded.
2. The 5V-3.3V LDO circuit of claim 1, wherein said IC converter chip is a SY8008BAAC chip.
3. The 5V-3.3V LDO circuit of claim 1, wherein the output voltage at the power supply output is VCC＝VFB(1+ R47/R52), varying the resistance values of R47 and R52 can vary the output voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022887166.3U CN214281235U (en) | 2020-12-03 | 2020-12-03 | 5V-3.3VLDO circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022887166.3U CN214281235U (en) | 2020-12-03 | 2020-12-03 | 5V-3.3VLDO circuit |
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| CN214281235U true CN214281235U (en) | 2021-09-24 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202022887166.3U Active CN214281235U (en) | 2020-12-03 | 2020-12-03 | 5V-3.3VLDO circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112865513A (en) * | 2021-02-04 | 2021-05-28 | 深圳市芯智科技有限公司 | Power supply bottom noise optimization method |
| CN114337209A (en) * | 2021-12-22 | 2022-04-12 | 上海御渡半导体科技有限公司 | Switching power supply module for reducing ripple noise and restraining method thereof |
-
2020
- 2020-12-03 CN CN202022887166.3U patent/CN214281235U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112865513A (en) * | 2021-02-04 | 2021-05-28 | 深圳市芯智科技有限公司 | Power supply bottom noise optimization method |
| CN114337209A (en) * | 2021-12-22 | 2022-04-12 | 上海御渡半导体科技有限公司 | Switching power supply module for reducing ripple noise and restraining method thereof |
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