| 摘要 |
A distribution charge pump is disclosed that reduces leakage from a VPP node where a programming voltage (VPP) is provided. The distribution charge pump includes a pump section and a biasing network. The pump section, in response to input signals at 0V or VCC, generates corresponding output signals at 0V or VPP, respectively. Typically, VCC can be between 2V and 5V and VPP can be between 11V and 15V. The pump section includes two n-channel transistors that bootstrap each other to cooperatively pull up the output node to VPP in response to an input signal of VCC. When the charge pump is active, one of the transistors, a native-mode device, transfers charge from the VPP node to an internal node where charge is stored by a capacitor. The biasing network reduces leakage current from the VPP node through the native-mode transistor when the charge pump is inactive. The biasing network accomplishes this by setting the voltage at the internal node when the charge pump is inactive so that the native-mode transistor is back biased and, therefore, off. The biasing network includes conventional transistors, one of which has a source coupled to a virtual ground signal that predominately determines the back-bias voltage level.
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