A Morimi new burst mode DC-DC regulator helps to reduce the size of the LED module

At present, the challenge for many LED applications is how to meet the requirements of LED power supply in the same size as incandescent or halogen lamps. In general, if a low current LED is used, the linear drive is the best solution. With the increase in power demand, or the voltage of the LED series is higher than the input voltage, then a switching regulator solution is needed. Although switching regulators are more flexible, the cost and size of the product are increased due to the need for an inductor.

The typical switching regulator topology for LED has the following three forms.

1 buck topology (Buck) - when all the operating conditions, the minimum input voltage is often higher than the maximum voltage of the LED series, the buck topology can be used. This is typically used to drive a single 1W Vdc powered by 12 Vac or 12 LED.

2 boost topology (boost) - when all the operating conditions, the maximum input voltage is often higher than the minimum voltage of the LED series, the boost topology can be used. This is typically used to drive 5 Vdc powered LED in series of 6.

3 buck boost or SEPIC - when the input voltage and output voltage overlap, the buck boost or SEPIC topology can be used. This is typically used for 12 Vdc car battery powered by the 4 series LED.

Historically, MC34063 switching regulators have been widely used to drive LED. It can flexibly configure the three topologies mentioned above. It can also achieve burst mode architecture, without the use of external compensation, easy to achieve more application design. The only challenge is to arrange a location for the new inductor. The switching frequency of MC34063 is ~50kHz, so a considerable inductor is required. A Morimi semiconductor's new product range offers the same ease of use, and a higher switching frequency. The higher switching frequency can be used with smaller inductors and also reduces the number of required output capacitors.

NCP3060 is a MC34063 pin compatible upgrade product. The operating frequency of the element is increased from 50kHz to 150kHz, so that the number of output capacitors can be reduced and the size of the inductor can be reduced. The output switch is also 1.5A. Typical applications of 24Vin to 5Vout MC34063 output capacitance of 470 F, inductor of LED H (see Figure 1). This reduces the size and cost of the product. Compared with the existing solutions, the product can also adopt a surface mount inductor which can only be installed in the through hole. NCP3063 pin compatibility in the absence of changes in the layout of the PCB, the existing MC34063 design can be removed from the output capacitor, replaced by smaller inductors. The improved drive capability of the NCP3063 can also be achieved at 150 kHz with the same system level efficiency as the 50 kHz MC34063, so the increase in switching frequency does not reduce system performance.

The burst mode architecture used in the NCP3163 is the same as the MC34063, but with new features and higher current output switch. NCP3163 has a 3.4A output switch. The larger output switch integration can achieve higher output current in a similar space range, thereby increasing the power density. It also has a space saving 5 x 6mm DFN package, and can improve the heat dissipation performance of the exposed pad SOIC-16WB package.

NCP3163 oscillator frequency can be adjusted to 250 kHz. This brings greater flexibility for designers to optimize system efficiency or save system space and cost. Under 50 kHz conditions, the typical MC34063 operating at 12Vin to 5Vout requires a capacitance of 2200 F, an inductor of + H 180. When the frequency is increased to 250 kHz, the required capacitance of the NCP3163 is reduced to 100 F, and the inductor is (H).

NCP3063 and NCP3163 for those who are already familiar with the LED application in the MC34063 design engineers to provide another convenient and versatile products. For those who have not previously applied to the burst mode architecture components, the inherent stability of NCP3063 and NCP3163 will make the deployment easier. The new features, improved frequency and improved heat dissipation enhancement package can make the design engineer to improve and upgrade the existing MC34063, to achieve a smaller space for the design of space constrained applications. This will help to reduce the size of the new LED module, reduce the cost of the previous generation of products, but also will further accelerate the process of incandescent lighting changes to LED.

Figure 1 - NCP3063 improved area and board space