Patents by Inventor Donovan Raatz

Donovan Raatz has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5749090
    Abstract: A cache TAG RAM (20) has a TAG array (22, 24) for storing TAG addresses of data stored in a cache memory, and a valid bit array (26, 31). In the cache TAG RAM (20), a valid bit is set for each TAG address to indicate if the TAG address is valid. The valid bit array (26, 31) is located separate from the TAG array (22, 24). During power-up of the cache TAG RAM (20), a multiple step invalidation cycle is used to sequentially invalidate groups of columns of the valid bit array (26, 31). The multiple step invalidation cycle reduces the peak current during an invalidation cycle, thus reducing metal migration.
    Type: Grant
    Filed: August 22, 1994
    Date of Patent: May 5, 1998
    Assignee: Motorola, Inc.
    Inventors: Taisheng Feng, Donovan Raatz
  • Patent number: 5497106
    Abstract: A BICMOS output buffer circuit (20) has a voltage converter (21), a reference voltage circuit (28), a driver circuit (24), and a clamping circuit (40). The reference voltage circuit (28) receives a regulated voltage and provides a reference voltage having a low voltage level and a high voltage level. The low voltage level and the high voltage level control the logic high voltage of an output data signal. During a transition from a logic low voltage to a logic high voltage of the output data signal, the output data signal is allowed to overshoot the low voltage level. After the transition is complete, the output data signal settles at the high voltage level. This limits the amount of overshoot of the output data signal. The clamping circuit (40) dampens the oscillations of the output signal.
    Type: Grant
    Filed: September 19, 1994
    Date of Patent: March 5, 1996
    Assignee: Motorola Inc.
    Inventors: Donovan Raatz, Taisheng Feng, Alan R. Bormann
  • Patent number: 5477176
    Abstract: A power-on reset circuit (30) for a memory (20) includes a DC model circuit (39), an N.sub.BIAS check circuit (64), and a NAND logic gate (71). A logic low power-on reset signal is provided at power-up of the memory (20) to establish initial conditions in a clock circuit (29) and in row and column predecoders/latches (24, 27). When the power supply voltage, a bandgap reference voltage, and a bias voltage all reach their predetermined voltages, the power-on reset circuit (30) provides a logic high power-on reset signal. In this manner, the power-on reset circuit (30) is assured of providing a logic low power-on reset signal until all of the proper voltage levels are reached. In addition, the power-on reset circuit models a DC circuit equivalent of an address buffer circuit (79) for compensating for process and temperature variations.
    Type: Grant
    Filed: June 2, 1994
    Date of Patent: December 19, 1995
    Assignee: Motorola Inc.
    Inventors: Ray Chang, Lawrence F. Childs, Kenneth W. Jones, Donovan Raatz, Stephen Flannagan