At times in electronic circuits containing high voltage circuit, a high voltage node needs to be sensed and divided down so that the low voltage control circuit may execute its function. However, the high voltage may peak to hundreds or thousands of volts while low voltage control circuits are typically in the order of ten volts. However, distorted voltage ratio in the divider resistive network may result due to varying resistances caused by voltage coefficient effect among resistor segments.
One prior art voltage sense method using external discrete resistors. This approach requires an extra pin and its own ESD structure, which consumes substantial silicon area. For low pin count package, this is either not allowed or undesirable. Another prior art voltage sense method is implemented in integrated circuit, which uses diffusion resistors or poly resistors. However, these resistors have to be segmented and each segment resistor must be in its own well tub to minimize voltage coefficient effect, which may distort voltage division ratio.
USPTO Backgrounds
USPTO Backgrounds