National aims to ease power supply design

According to National, the new regulators feature a combination of high performance, flexibility and ease of use in dc/dc power supply designs. Mal Humphrey, product line director for the company’s Power Management Group, said the aim was to make switching power supply design easy for the end user. “Our customers are mainly embedded designers,” he claimed, “and power supply design is not their prime area of expertise.” Humphrey noted that National has been determining what the ‘ideal solution’ would be for about a year. “We started with maintaining ease of use and design, but added a couple of other things including flexibility and higher power levels.” The new regulators feature an input of up to 75V and can deliver a continuous output of up to 3A. The emulated current mode approach is said to provide superior load transient response in low duty cycle applications that are not addressable by traditional current mode control. Meanwhile, operating frequency is adjustable from 50kHz to 1MHz. Emulated current mode control is said to overcome the noise susceptibility of current mode control by emulating the buck switch current signal, and using that for current mode control. The emulated buck switch current signal is the sum of an emulation ramp current and the sampled diode current just before switching occurs. Avoiding direct buck switch current measurement minimises the effect of switching noise, while maintaining the benefits of the current mode control.