Device and method for supplying current to a semiconductor memory to support a boosted voltage within the memory during testing

摘要

A Dynamic Random Access Memory (DRAM) device includes a bus for distributing a boosted voltage V_CCP within the device. A conventional internal voltage regulator, ring oscillator, and charge pump help to boost the boosted voltage V_CCP on the bus when the voltage V_CCP falls below a preset minimum. During testing of the DRAM device, when the demand on the boosted voltage V_CCP can be four or more times as much as it is under normal operating conditions, an external current source drives current I_CCP into an unused bond pad, such as a no-connection (NC) or address signal bond pad. An NMOS transistor switch then connects this bond pad to the boosted voltage V_CCP bus when a pump circuit controlled by the ring oscillator activates the switch. As a result, the external current augments the efforts of the internal charge pump to boost the voltage V_CCP during testing, so there is no need to build the internal charge pump with oversized capacitors to handle the excessive V_CCP demand during testing.