Abstract: This invention relates to device for detecting a threshold value of the frequency of an input signal. A gate signal is generated from the input signal, whose period has a relationship to the frequency of the input signal. A counter counts pulses from an oscillator having a predetermined rate. The gate signal enables the counter for a predetermined period of time and samples the count at the end of the period of time to determine whether the threshold value has been attained, the count stored in the counter being indicative of the frequency of the input signal.

Abstract: An annunciator arrangement includes a segmented display unit with segments which may be selectively activated. There is also provided scanning means for scanning a fault line from each of a number of computer components such as voltage regulators to determine the presence or absence of a fault signal thereon. Logic circuitry is provided for selectively displaying on the segmented display units a numerical indication representative of the particular fault line upon which a fault signal has been detected. Such annunciator display is provided at the control panel of the computer rendering it unnecessary for the operator thereof to access the inward parts of the computer in order to determine which component of the computer is indicated as failing.

Abstract: The present invention relates to a power sequence device which comprises an element which generates a sequencing code which is capable of being decoded by actuators included in the various equipment cabinets. The sequencing code is initiated by a sensing element which indicates the input power has reached a stable threshold whereupon the various cabinets comprising the data processing system are turned on in a desired order. Upon loss of power, the sensing element generates a warning signal indicating an impending power loss thereby enabling the equipment to perform an orderly halt.

Abstract: The present invention relates to a power supply which includes a switching regulator and an over-current detector, having a reference circuit for providing an over-current threshold level. A means is provided by the present invention for adjusting the over-current threshold level without interrupting the system by utilizing a switch to provide an inhibit signal to a fault shut down circuit and for inserting a component into the reference circuit to modify the over-current threshold level to the desired adjustment level.

Abstract: A maximum frequency detector having a counter which counts through a certain number of counts unless an inhibit signal is received at a rate determined by the frequency of the clock pulse received. The inhibit signal is generated by a logic network to prevent the counter from producing an outgoing digital pulse of the digital pulse stream. The counter, the clock pulse generator and the logic network cooperate to have the frequencies of the incoming and outgoing digital pulses equal unless the incoming digital pulse stream has its frequency exceed the predetermined maximum frequency. In the event that the frequency of the incoming digital pulse stream exceeds the predetermined maximum frequency the frequency of the outgoing digital pulse stream is the certain predetermined maximum frequency.

Abstract: A control apparatus for a switching regulator circuit having a voltage controlled oscillator responsive to any deviation of the output voltage of the switching regulator circuit from a predetermined reference voltage. The voltage controlled oscillator produces a digital pulse stream having a frequency which is varied by the voltage controlled oscillator in response to any deviation of the output voltage of the switching regulator circuit from the predetermined reference voltage. A recovery detector is connected to at least one of the reactors of the switching regulator circuit to ensure that the particular SCR associated with that reactor has fully recovered prior to the next actuation thereof. If the particular SCR has not recovered then the digital pulse which would be distributed to that SCR within the digital pulse stream is held.

Abstract: An apparatus for detecting each short circuited diode in a plurality of diodes, coupled in a parallel combination, is disclosed. The apparatus utilizes a flashing light emitting diode to indicate whether the particular diode under test is shorted or not. By utilizing the series inductance associated with each diode circuit, effective isolation of the particular diode under test is obtained for a short duration test pulse and allows the appropriate test to be made.

Abstract: An improved high current low voltage switching regulator power supply in which the major heat producing components of the power modules of the power supply are mounted on a pair of chill plates with a liquid cooled heat exchanger between the plates. The chill plates are electrically isolated from each other and the heat exchanger. One chill plate also serves as the positive power output bus and the other as the negative power output bus of the power supply which significantly reduces the parasitic inductance of the power supply.