Abstract: An N-channel transistor protection circuit and method are disclosed that prevent gated diode breakdown in N-channel transistors that have a high voltage on their drain. The disclosed N-channel protection circuit may be switched in a high voltage mode between a high voltage level and a lower rail voltage. A high voltage conversion circuit prevents gated diode breakdown in N-channel transistors by dividing the high voltage across two N-channel transistors, MXU0 and MXU1, such that no transistor exceeds the breakdown voltage, Vbreakdown. An intermediate voltage drives the top N-channel transistor, MXU0. The top N-channel transistor, MXU0, is gated with a voltage level that is at least one N-channel threshold, Vtn, below the high voltage level, Vep, using the intermediate voltage level, nprot.

Abstract: A switching circuit is disclosed for switching high voltages and high currents, if necessary, without causing snapback or breakdown. The disclosed high voltage, high current switching circuit comprises a first set of series-connected transistors that includes a plurality of transistors to switch a high voltage without inducing snapback or breakdown; and a second set of series-connected transistors that includes one or more transistors to switch a high current. The first and second sets of series-connected transistors are connected in parallel. The gates of the second set of series-connected transistors are enabled to cause conduction through the second set of series-connected transistors. In addition, a voltage detector is connected to an output of the first and second sets of series-connected transistors. The output of the voltage detector is coupled to the enabling means.

Abstract: A single chip embedded microcontroller has a processor that communicates with multiple non-volatile erasable PROMS which may be an OTPROM and an EEPROM. The processor also communicates with a high voltage generator that produces the erase and write voltages for the OTPROM and EEPROM. A switch communicates with the high voltage generator and switches the erase and write voltages alternately between the OTPROM and EEPROM. The OTPROM and EEPROM are FLASH arrays. The FLASH array technology allows the EEPROM and OTPROM to have similar erase and write voltages and therefore to share one high voltage generator. The high voltage generator is switched alternately between the first and second non-volatile erasable PROM arrays to enforce the principle that the EEPROM and OTPROM cannot be written to or erased at the same and may only be written to or erased one at a time.

Abstract: A semiconductor circuit is disclosed that contains test hardware or test software (or both) that allows test functions to be executed directly from the memory of the semiconductor circuit. A remote testing station can issue a command indicating a specific test function that should be implemented. The disclosed semiconductor circuit independently performs the indicated test and provides the results to the test station. For an exemplary memory test, the test hardware and test software are employed to initially clear the memory and thereafter selectively apply a pattern to memory and read the applied pattern from each address to confirm that the correct pattern has been stored. The testing technique of the present invention reduces the number of pins that must be contacted by the tester, such as the address pins. In addition, the reduced number of contact points allows a number of semiconductor circuits to be setup and tested in parallel using the same automated test equipment (ATE).

Abstract: A method and apparatus are disclosed for detecting if a semiconductor circuit has been exposed to ultra-violet light. An ultra-violet light detection circuit detects exposure to ultra-violet light and will automatically activate a security violation signal. The security violation signal may optionally initiate a routine to clear sensitive data from memory or prevent the semiconductor circuit from further operation. The ultra-violet light detection circuit detects whether a semiconductor circuit has been exposed to ultra-violet light, for example, by employing a dedicated mini-array of non-volatile memory cells. At least two active bit lines, blprg and bler, are employed corresponding to program and erase, respectively. One of the bit lines is only programmable and the other bit line is only eraseable. Generally, all of the bits in the dedicated non-volatile memory array are initially in approximately the same state, which could be erased, programmed or somewhere in between.

Abstract: An emulated EEPROM memory array is disclosed based on non-volatile floating gate memory cells, such as Flash cells, where a small group of bits share a common source line and common row lines, so that the small group of bits may be treated as a group during program and erase modes to control the issues of program disturb and effective endurance. The bits common to the shared source line make up the emulated EEPROM page which is the smallest unit that can be erased and reprogrammed, without disturbing other bits. The memory array is physically divided up into groups of columns. One embodiment employs four memory arrays, each consisting of 32 columns and 512 page rows (all four arrays providing a total of 1024 pages with each page having 8 bytes or 64 bits). A global row decoder decodes the major rows and a page row driver and a page source driver enable the individual rows and sources that make up a given array.