Battery test system, as for smoke detector alarm
First Claim
1. In a battery powered alarm circuit having first and second battery terminals for receiving a battery potential therebetween, a sensor for detecting an alarm condition, means responsive to said sensor for providing an alarm control signal, an annunciator responsive to said alarm control signal for sounding an alarm, and a capacitor for providing starting current for said annunciator, a test system for determining a high series resistance condition of said battery, said test system comprising:
- means for drawing a test current pulse from said battery, said means having a test pulse signal indicating said test current pulse;
switch means having a principal current conduction path, and a control electrode, the potential on said control electrode determining the conductivity of said principal current conduction path, said switch means having its principal current conduction path connected in series with said starting capacitor;
logic control means responsive to said alarm control signal and said test pulse signal, said logic control means having an output terminal connected to the control electrode of said switch means for conditioning said switch means for conduction at least during said alarm control signal, and for conditioning said switch means for nonconduction at least during said test pulse signal, so that said starting capacitor does not discharge substantial current during said test current pulse; and
test means responsive to said test current pulse for indicating a high series resistance condition of said battery.
2 Assignments
0 Petitions
Accused Products
Abstract
A system for use in battery powered alarm equipment for self-testing such battery for a low voltage and a high series resistance condition, and particularly for use in systems which utilize a starting capacitor in combination with the battery to provide a high starting current to the alarm annunciator. For periodic battery tests, a resistor is selectively connected across the battery and the resulting voltage drop at the battery terminals is compared to a reference voltage supply. Energy stored in the starting capacitor is prevented from discharging through the battery test circuit by a transistor switch operated in the inverse mode for disconnecting the starting capacitor from one of the battery terminals during such battery tests so that substantially no current is supplied from the starting capacitor through the test circuit. When the alarm is activated, the transistor switch is operated in the normal mode to connect the starting capacitor in parallel with the battery to provide starting current for the alarm. When the alarm annunciator is not activated, the starting capacitor is maintained at substantially full battery voltage.
19 Citations
12 Claims
-
1. In a battery powered alarm circuit having first and second battery terminals for receiving a battery potential therebetween, a sensor for detecting an alarm condition, means responsive to said sensor for providing an alarm control signal, an annunciator responsive to said alarm control signal for sounding an alarm, and a capacitor for providing starting current for said annunciator, a test system for determining a high series resistance condition of said battery, said test system comprising:
-
means for drawing a test current pulse from said battery, said means having a test pulse signal indicating said test current pulse; switch means having a principal current conduction path, and a control electrode, the potential on said control electrode determining the conductivity of said principal current conduction path, said switch means having its principal current conduction path connected in series with said starting capacitor; logic control means responsive to said alarm control signal and said test pulse signal, said logic control means having an output terminal connected to the control electrode of said switch means for conditioning said switch means for conduction at least during said alarm control signal, and for conditioning said switch means for nonconduction at least during said test pulse signal, so that said starting capacitor does not discharge substantial current during said test current pulse; and test means responsive to said test current pulse for indicating a high series resistance condition of said battery. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
Specification