Part of Inomize activity is designing the PMUs (Power Management Unit) of the chips, as well as standalone PMIC (Power Management ICs). These designs include DC-DC converters, since many applications require a regulated supply from an input source. This source may be greater than or less than the desired output voltage. Such applications place unique constraints on the DC-DC converter and generally add complexity and cost to the power supply.

When designing a power supply, it is essential to choose the right power supply topology. Making the wrong choice means unhappy customers and losing time and money. When looking at voltage regulation, the usual trade-offs of size, efficiency, accuracy and voltage ripple are important, but so is the topology of the solution. Should it be an inductor-based converter, linear regulator (LDO) or charge pump?

Using an LDO for these applications may result in inefficiency issues although being the trivial and simplest solution.

On the other hand, charge pump ICs aren’t the optimal solution for every design due to their limited output current. However they do possess several advantages over an inductive converter and increased efficiency over an LDO.

And last, inductor based are the most efficient power supply devices, however they carry in most cases the most expensive design in many terms.

Summing up the pros and cons of the several options leads to the below table.

Power Management Unit of ICs

Type of circuit       advantages               disadvantages

 
LDO
 
 
CHARGE PUMP
 
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INDUCTOR BASED
  • Simple
  • Lowest cost
  • No EMI
 
  • No inductor
  • Low cost
  • Smallest PBC area
  • More efficient than LDO
  • Most efficient
  • Larger loads possible (250mA+)
  • Least efficient
 
 
  • Low, moderate loads (<10mA)
  • EMI
  • Most expensive
  • Complex design
  • Greater PCB area and height
  • EMI

Hence it is crucial to understand the entire system design constraints and consider which of the techniques to pick. Selecting the optimal technique may require several engineers from various expertise to make sure all trade offs were taken care of.

At Inomize, we worked on projects using BCD process handling wide high voltage range up to 80V in conjunction with low voltage digital and analog circuitry. Designs include multiple step-up and step-down DC conversion on the same die. We developed switched capacitors step-up, H-bridge step-down charge pumps and LDOs. The switched designs also include multiple outputs buck and boost converters with high-power external and/or medium-power internal switching transistors.

Auxiliary circuitry of the above designs includes bandgaps, temperature sensors, high resolution ADCs for sensors and loop control DACs. Some of these designs are being controlled digitally using an internal or external micro-processor or external circuitry using SPI, I2C or I3C interfaces.

At Inomize, we also make designs combining several domains (digital, analog, RF and high voltage) in many projects, thus we excel in understanding the consequences of selecting the right route for every designs. Get in touch to learn more.