| 摘要 |
A high voltage current source and a voltage expander (250) implemented in a low voltage semiconductor process. The voltage expander extends the operating voltage range of a stack of transistors to k times the supply voltage Vdd at the output node of the stack without exceeding the breakdown voltage of any of the transistors in the stack. The voltage expander uses a diode (220) and a voltage divider (215) to detect the output node voltage (Vout) changes and generates a plurality of voltages (Vgk-1) that control the gate voltages for the stack of transistors (213-1,213-k-1). A high voltage wide swing current source utilizes a transistor to set the output current and the voltage expander to extend the output voltage range of the current setting transistor. An additional transistor and another current source ensure that the output current is constant throughout the entire output voltage range between about 0V and k x Vdd.
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