Power Management in Noise-Sensitive Applications

Time:2014-03-11 Reading:41

Table 2 lists switching dc/dc step-down converters with desirable features for broadcasting applications.

Supplier Device Vin (V) Vout (min)
(V)
Iout Output Voltage
Ripple (mVpp)
Switching
Frequency
Freq
Synch
Power
Seq
Soft
Start
Power
Good
Intersil ISL8206M
Power module
1 to 20 0.6 6 8 600 kHz No No Yes No
On Semi NCP1592
Switcher with
integrated FETs
3 to 6 0.891 6 10 280 kHz to 700 kHz Yes No Yes Yes
TI TPS54620
Switcher with
integrated FETs
4.5 to 17 0.8 6 33 (per EVM) 200 kHz to 1.6 MHz Yes Yes Yes Yes
TI TPS84621
Power module
2.95 to 14.5 0.6 6 30 250 kHz to 780 kHz Yes Yes Yes Yes

 

Integration

If board space is at a premium, consider the modern power management solutions that integrate the switching DC/DC converter and post-regulation linear regulator into a single, small package. One such example is the TPS54120 from TI. Introduced only a little over a year ago in 2012, this device combines a high-efficiency switching DC/DC converter with a low-noise, high PSRR low-dropout linear regulator to support 1-A, noise-sensitive applications. The TPS54120 also includes switching frequency synchronization, soft-start, and power-good indication in a space-saving 3.5-mm x 5.5-mm thermally-enhanced QFN package.

Conclusion

In summary, power supply noise reduction is a complex subject. Part of a good power distribution system design is in choosing the right voltage regulators, the considerations of which have been mentioned. However, keep in mind that there are other important factors that are beyond the scope of this article, including proper bypassing, decoupling, damping, PCB layout, and much more. Thankfully, the internet is a great resource for additional information on these topics.

Landa writes from Dallas, TX. She holds a BSEE, and has 18 years experience in the electronics industry, from tech startups to Fortune 500 companies.

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