NOVEI DESIGN OF INTERNAL POWER SUPPLY FOR HIGH-VOLTAGE DC-DC CONVERTER

摘要

Switching integrated DC-DC converters have become the solution of choice for power management in automotive electronics due to the advantages they offer, including high efficiency However, new challenges are facing the converter design, brought on by the requirements for wide input voltages and load range in automotive, telecommunication and industrial systems, as well as battery-powered handheld devices. Both high and low power is needed for a general high-voltage DC-DC converter. The high-input-power supplies energy to the internal high-side driver and other high-voltage modules, while the low internal-power supplies the internal low-voltage module. Therefore, a low-voltage internal power-supply is required to be generated from the high-voltage input inside the chip. In order to overcome this problem, we suggest an internal power-supply structure for high-voltage buck DC-DC converters, which consists of a pre-bias and soft reference generating circuit, multiplex differential input linear regulator and a power grouping isolation circuit. The pre-bias and soft reference generating circuit provides bias current and soft reference voltage for the linear voltage regulator. After the 1.2 V zero temperature coefficient voltage produced by a bandgap reference circuit is established, a soft reference voltage will automatically switch to a 1.2 V reference voltage to make the linear regulator generate a precise internal power supply of 5 V. By lifting V_(GS) (gate-source voltage), the power grouping isolation circuit produces four non-interfering analog, digital, power and bootstrap internal power supplies.