초록 ▼

Disclosed is a standby power supply system appropriate to supply a set of signal amplifiers within a cable television network. The standby power supply normally operates off of utility company power and alternatively operates from a battery power supply during power failures. Circuitry is disclosed

Disclosed is a standby power supply system appropriate to supply a set of signal amplifiers within a cable television network. The standby power supply normally operates off of utility company power and alternatively operates from a battery power supply during power failures. Circuitry is disclosed to use battery power during failure mode operation to generate a pulse width modulated alternating current of substantially constant true rms voltage and of substantially constant frequency. Circuitry is also disclosed to cycle charge the battery supply to a desired voltage and then stop the charging cycle and begin timing normal mode operation until another charging cycle. Further, isolating circuitry is disclosed to remove much of the load on the battery supply during normal mode operation. Various safety provisions including soft start provisions, a high current cut off, a low voltage cut off, and protection for the amplification stages is included. Finally, various types of status monitoring equipment are disclosed.

대표청구항 ▼

A standby power supply for supplying power to a cable from an a-c utility source when available, and for supplying substantially constant frequency a-c power from a float service battery powered circuit to said cable when said utility source is unavailable, comprising: means for converting the utili

A standby power supply for supplying power to a cable from an a-c utility source when available, and for supplying substantially constant frequency a-c power from a float service battery powered circuit to said cable when said utility source is unavailable, comprising: means for converting the utility supplied voltage to cable voltage and for normally applying said converted voltage to said cable; means for connecting said battery powered circuit to said cable upon failure of said utility source, and for reapplying said utility source to said cable upon restoration of said utility source; a battery converting circuit converting the battery voltage to a-c voltage of substantially the same frequency as said utility source for application to said cable, said battery converting circuit comprising: means for measuring a voltage applied to said cable by said battery converting circuit; means for generating pulses of substantially constant frequency and of variable width, responsive to said voltage measuring means to vary the width of said pulses to maintain the voltage applied to said cable by said battery converting circuit substantially constant, despite decay in the battery voltage and despite varying loads applied to the standby power supply; an amplifier controlled by said pulse generating means for amplifying said pulses to the voltage desired for application to said cable by said battery converting circuit; means for charging said battery, including: rectifying means for producing a d-c charging currrent from said a-c utility source; means for measuring a desired time interval between charging cycles of said battery; means responsive to said time measuring means for applying the charging current to said battery upon the elapsing of said time interval; means responsive to a discharge condition of said battery for applying the charging current to said battery when said discharge condition falls below a predetermined level; and means responsive to battery use for applying the charging current to said battery after said battery has been used to supply power to said cable; means responsive to the voltage on said battery for removing said charging current from said battery when said voltage reaches a desired level; and means responsive to said charging current removing means for resetting said clock means to initiate a succeeding desired time interval measurement.