Please recommend a 5V to positive and negative 15V op amp power supply circuit or chip to share

qwqwqw2088 · Published on 2020-10-22 14:03

Please recommend a 5V to positive and negative 15V op amp power supply circuit or chip to share [Copy link]

Convert USB power supply to positive and negative 15V power supply, which can power 3 op amps. The power consumption of op amp is about 300MW, which should be enough. Please recommend related circuits or chips

qwqwqw2088 · Published on 2020-10-22 14:05

TPS65130- http://www.ti.com.cn/product/cn/TPS65130

The circuit structure is as follows

qwqwqw2088 · Published on 2020-10-22 14:07

In addition, there are flyback isolation solutions such as LM2587 and LM2588. The circuit structure is as follows. You can use webench software to assist in the design.

qwqwqw2088 · Published on 2020-10-22 14:09

It seems that the current requirement of the op amp is not large. It is recommended to use chips such as TI's TPS61081:

http://www.ti.com.cn/general/cn/docs/lit/getliterature.tsp?genericPartNumber=tps61081&fileType=pdf

See the circuit design of Figure 25 on page 18 of the above datasheet, which is the TPS61080, 5V to +/-15V/30mA circuit:

qwqwqw2088 · Published on 2020-10-22 14:11

This post was last edited by qwqwqw2088 on 2020-10-22 14:12

The above chip uses TPS61080. If TPS61081 is used, it can achieve a larger output current to meet your needs, and the circuit is relatively simple.

What is the output ripple of this TPS61080 circuit?

The positive 15V output has feedback and should be stable. The negative 15V output has no feedback loop. So, will it have a big impact if the ±15V voltage is loaded on the op amp?

qwqwqw2088 · Published on 2020-10-22 14:12

The +/-15 is symmetrical so only one feedback is needed.

The dual power supply design of TPS61080 is designed for dual power supply applications such as op amps. If the op amp requirements are very high, an additional LDO can be added.

As for TPS61080, the output ripple is not large (should be less than 50mV) from the datasheet. Alternatively, you can add a 4.7uF or 10uF capacitor in parallel to the output 4.7uF capacitor to stabilize the voltage, which should be better. In addition, you can also add feedback capacitors based on this circuit, which can improve the output.