Abstract: An intrinsic safety approach is provided for a battery powered communication device. Sparking is prevented at radio contacts during attachment and removal of a battery (104, 204, 304, 404) from a radio (102, 202, 302, 402) through the use of switches (112, 212, 312, 412/424) to isolate the radio capacitors from the radio contacts and/or dissipate energy from the radio capacitor through a discharge resistor (214, 314, 414).

Abstract: Embodiments include a power supply arrangement where major components including an off-line switched power supply are shut off when not in use. When a load is coupled to the power supply arrangement, components are enabled so as to provide power to the load.

Abstract: Embodiments include a power supply arrangement where major components including an off-line switched power supply are shut off when not in use. When a load is coupled to the power supply arrangement, components are enabled so as to provide power to the load.

Abstract: A system for detecting liquid on a battery or on an electronic device connected with the battery is presented. The battery has an electrical contact for transferring current from the battery to the electronic device. The system includes a sensor for detecting liquid on the battery or on the electronic device and sensor circuitry connected with the sensor. The sensor circuitry prevents current from flowing through the electrical contact of the battery upon detecting liquid.

Abstract: A portable radio and battery pack configuration favoring higher available transmit power in explosive atmosphere applications includes a radio device (302) and a battery pack (304) removably attached to the radio device. The battery pack includes at least one of an audio power amplifier (346) and a radio frequency (RF) power amplifier (356), and a battery (306) for supplying power to the radio device and to the at least one of an audio power amplifier and a RF power amplifier.

Abstract: An intrinsic safety approach is provided for a battery powered communication device. Sparking is prevented at radio contacts during attachment and removal of a battery (104, 204, 304, 404) from a radio (102, 202, 302, 402) through the use of switches (112, 212, 312, 412/424) to isolate the radio capacitors from the radio contacts and/or dissipate energy from the radio capacitor through a discharge resistor (214, 314, 414).

Abstract: A system for detecting liquid on a battery or on an electronic device connected with the battery is presented. The battery has an electrical contact for transferring current from the battery to the electronic device. The system includes a sensor for detecting liquid on the battery or on the electronic device and sensor circuitry connected with the sensor. The sensor circuitry prevents current from flowing through the electrical contact of the battery upon detecting liquid.

Abstract: A portable radio and battery pack configuration favoring higher available transmit power in explosive atmosphere applications includes a radio device (302) and a battery pack (304) removably attached to the radio device. The battery pack includes at least one of an audio power amplifier (346) and a radio frequency (RF) power amplifier (356), and a battery (306) for supplying power to the radio device and to the at least one of an audio power amplifier and a RF power amplifier.

Abstract: A method for providing cooled flip chip is provided. Solder paste is placed on a back side of a flip chip. A heat sink is placed against the solder paste. The solder paste is reflowed. In addition, an apparatus is provided. Generally, a zener diode flip chip with an active side and a back side opposite the active side and a positive thermal coefficient resistor are provided. A thermally conductive connection is between the positive thermal coefficient resistor and the back side of the zener diode flip chip.

Abstract: This invention includes a thermally stable, low-cost charging circuit for rechargeable batteries. The circuit includes a thermal control circuit that employs a temperature dependent component such as a thermistor or positive temperature coefficient device. The temperature dependent device is thermally coupled to a charging pass element, which is typically a power transistor. When the transistor enters a danger zone, which is a region of operation characterized by elevated power dissipation in the pass element, the thermal control circuit is actuated to regulate the pass element in a constant power mode until the circuit exits the danger zone.

Abstract: A transient rejecting system for protecting the state of a memory is described. The transient rejecting system includes a signal transfer circuit and a charge storage circuit coupled to at least one pin of a circuit. The signal transfer circuit receives a supply signal and determines when a transient event occurs. When a transient event occurs, the charge storage circuit provides a signal to the pin of the circuit maintaining the state of the memory prior to the transient. During normal operation, the charge storage circuit is charged, and the supply signal is provided to the pin of the memory circuit. P-channel FETs are used in the signal transfer circuit and allow for low voltage operation of the transient rejecting system.

Abstract: This invention includes a thermally stable, low-cost charging circuit for rechargeable batteries. The circuit includes a thermal control circuit that employs a temperature dependent component such as a thermistor or positive temperature coefficient device. The temperature dependent device is thermally coupled to a charging pass element, which is typically a power transistor. When the transistor enters a danger zone, which is a region of operation characterized by elevated power dissipation in the pass element, the thermal control circuit is actuated to regulate the pass element in a constant power mode until the circuit exits the danger zone.

Abstract: A battery charging circuit comprises a recharge input and a recharge output with a switching element electrically coupled in series between the recharge input and output. A recharge controller controls a conducting state of the switching element. When in a conducting state, recharge current can flow from the recharge input to the recharge output, thereby allowing a rechargeable battery coupled to the recharge output to be recharged. During periodically occurring intervals, the recharge controller switches the switching element to a non-conducting state such that the recharge current no longer flows to the recharge output. During the intervals, a battery voltage input is sampled to determine a charge state of the battery. The switching element is subsequently returned to a conducting state when further recharging is necessary, or left in a non-conducting state when sufficient recharging has occurred.

Abstract: A voltage regulator that includes a transistor, a first amplifier and a second amplifier. The voltage regulator maintains a voltage between a first node and a second node within a predetermined range by maintaining a current level flowing from the first node to the second node. The transistor has a first pole electrically coupled to the first node, a second pole electrically coupled to the second node and a gate. The first amplifier has a first input, a second input and an output, and the second amplifier has a first input, a second input and an output, wherein the first inputs of the first and second amplifiers are electrically coupled to the first node, the second inputs of the first and second amplifiers are electrically coupled to the second node, and the outputs of the first and second amplifiers are electrically coupled to the gate of the transistor, respectively. The first and second amplifiers have different characteristic response times to reach a saturation voltage value.

Abstract: A voltage regulator that includes a voltage control circuit, fabricated on a semiconductor. The voltage control circuit maintains a voltage between a first node and a second node within a predetermined range by maintaining a current level flowing from the first node to the second node. The current level is a function of a voltage between a third node and the second node. A thermal sensing circuit is also fabricated on the semiconductor and is thermally coupled to the voltage control circuit. The thermal sensing circuit asserts a latch signal that causes the voltage control circuit to allow a saturation value of current to flow from the first node to the second node when the thermal sensing circuit senses that the voltage control circuit has reached a temperature above a predetermined threshold.

Abstract: A battery charging system 100 is provided which comprises a charger 101 and a battery pack 102. The battery pack 102 comprises a battery cell or cells 150, memory means 140, temperature sensing means 147, and a high accuracy, high impedance voltage sensing means 112 that senses voltage directly at the battery cell terminals 151, 149. By sensing directly at the cell terminals 151, 149, charging error due to parasitic conductor impedances 132, 138 can be eliminated. The voltage sensing means 112 allows memory 140 and thermistor 147 data to be multiplexed, allowing the system to operate with four or fewer battery terminals.

Abstract: A digital control circuit is used for controlling the load current of a power converter circuit (102), and comprises a reference circuit (302), analog comparator circuit (304), control logic circuit (306), and a counter circuit (308). The control logic circuit controls the operation of a power switch (110), and uses counters (314, 316) in conjunction with the analog comparator circuit and reference circuit, to determine when to open and close the power switch. The load current is allowed to vary between a first and second preselected load current levels.

Abstract: A dual range power supply 200 is operable with either an AC line input, or a DC input. To facilitate use with an AC input the power supply is provided with a pair of AC prongs, connected to a rectifier bridge. The power supply is also provided with a positive DC receptacle. In using the power supply with a DC source, the power supply is connected to an adapter. The adapter has receptacle slots for receiving the AC prongs of the power supply, and a positive DC prong which mates with the positive DC receptacle of the power supply. Positive DC power is applied to the power supply through the positive DC receptacle while the DC return is through the rectifier bridge and at least one of the AC prongs.

Abstract: A battery charger (10) avoids discharging a battery (12) when the battery is connected to the charger and the charger is unpowered. The charger comprises a control circuit (18) which is switchably connected to an input power line (26) by a switch (28). The switch is actuated by a circuit which is responsive to the input voltage, and causes the switch to close only when the input voltage is above a preselected level, which is preferably substantially higher than the nominal battery voltage.

Abstract: A battery pack (12) comprises current sensor (28) for sensing the charge current through a battery cell (26), and generating a DC voltage which is sensed by a charger (14). The charger can then provide an output current that satisfies both the need for a constant charge current through the battery cell or cells, and the varying current demand of a load (10). Additionally, the battery pack may include a switch (34) for removing the current sensor from the discharge path of the battery cell or cells and the load when the battery pack is not connected to the charger.