Browse Prior Art Database

Ripple Counter

IP.com Disclosure Number: IPCOM000093077D
Original Publication Date: 1967-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Johnson, ET: AUTHOR

Abstract

This ripple counter is loadable and can count either up or down as required. A three-stage counter comprising three binary-connected trigger circuits 10 is shown but the counter can have any number of stages. In the logic shown, the trigger requires a positive going AC pulse to flip it.

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Ripple Counter

This ripple counter is loadable and can count either up or down as required. A three-stage counter comprising three binary-connected trigger circuits 10 is shown but the counter can have any number of stages. In the logic shown, the trigger requires a positive going AC pulse to flip it.

To load bits from a register, the load cycle is initiated. First, each trigger 10 is reset over common reset line 12. Also, the preload time pulse 44 is applied to the -OI's 46...48 and the count up and down gates 54 and 52 are inhibited at this time. With these conditions set, load time pulse 40 gates register bits 1, 2, and 4 in +AI's 30...32 which set triggers 10 via -OI's 57...59 at the end of load time. With the proper bits now loaded in the counter from the register, the countup and countdown gates are now restored as shown in waveforms wave 54' and 52'. The solid line is countup, the dashed line is countdown. Finally, the preload time gate is dropped, disconnecting the load time circuits 30...32 and 46...48 to end the load cycle. The timing sequence of the load cycle waveforms is critical in order to avoid false counting or loading.

Now, the counter is ready to count up or down one bit each time the asynchronous count time pulse 56 is applied to -OI 57 from the binary value originally loaded during the load cycle. This is done in a standard ripple counter manner. It is necessary to initiate a load cycle before a new value is loaded into the bit register if th...