Heater with flame powered logic supply circuit

In a heater assembly having a main burner intermittently ignited by a pilot flame, a flame powered logic supply circuit responsive to said pilot flame and supplying electrical energy to power electronic logic circuitry for the heater assembly, said supply circuit comprising:

• a thermoelectric element responsive to said pilot flame and outputting electrical current;
• a first electrical energy storage component coupled to said thermoelectric element;
• a pair of parallel circuit branches coupled to said thermoelectric element and said storage component,
• the first of said circuit branches comprising a semiconductor switch having an on state completing a circuit therethrough from said thermoelectric element such that current flow through said last mentioned circuit supplies energy to said storage component which is stored therein, said semiconductor switch having an off state blocking current flow in said first circuit branch such that current from said thermoelectric element flows through the second of said circuit branches,
• said second circuit branch comprising a second energy storage component receiving current from said thermoelectric element and from said first storage component when said semiconductor switch is in said off state, to supply energy to said second storage component, including stored energy supplied from said first storage component to said second storage component, to maintain a given power rating of said second storage component for powering said electronic logic circuitry of said heater assembly;
• monitoring circuitry monitoring the energy stored in said first storage component and controlling said semiconductor switch between said on and off states to release said stored energy from said first storage component to said second storage component during said off state of said semiconductor switch, and to re-supply energy to said first storage component during said on state of said semiconductor switch.

In a heater assembly having a main burner intermittently ignited by a pilot flame, a flame powered logic supply circuit responsive to said pilot flame and supplying electrical energy to power electronic logic circuitry for the heater assembly, said supply circuit comprising:

• a thermoelectric element responsive to said pilot flame and outputting electrical current, said thermoelectric element having first and second terminals;
• an inductor connected in series between said first terminal of said thermoelectric element and a first node;
• a current sensing resistor connected in series between said second terminal of said thermoelectric element and a second node;
• a semiconductor switch connected in series between said first and second nodes, said switch having a first terminal connected to said first node, a second terminal connected to said second node, and a control terminal for controlling conduction of said semiconductor switch between an on state conducting current between said first and second terminals of said semiconductor switch, and an off state blocking current flow between said first and second terminals of said semiconductor switch;
• a battery connected in series between said first and second nodes, and in parallel with said semiconductor switch;
• a comparator having an output connected to said control terminal of said semiconductor switch, a first input connected to said second terminal of said thermoelectric element, a second input connected to said second node, and a feedback connection between said output of said comparator and one of said inputs of said comparator,
• such that during said on state of said semiconductor switch, current flows from said thermoelectric element through said inductor through said semiconductor switch through said current sensing resistor and back to said thermoelectric element, said inputs of said comparator sensing the voltage across said resistor such that when the voltage at the other of said inputs reaches a first given level relative to the voltage at said one input, said output of said comparator transitions to turn off said semiconductor switch, the output level of said comparator being communicated back through said feedback connection to said one input of said comparator to change the switching threshold reference level thereat,
• and such that during said off state of said semiconductor switch, current flows from said thermoelectric element through said inductor through said battery through said current sensing resistor back to said thermoelectric element to transfer stored energy from said inductor to said battery during said off state of said semiconductor switch, such that said battery is charged by said current and is also charged by the energy previously stored in said inductor during the above noted previous on state of said semiconductor switch, to maintain a given power rating of said battery for powering said electronic logic circuitry of said heater assembly, said inputs of said comparator sensing the voltage across said resistor during said off state of said semiconductor switch such that when the voltage at said other input reaches a second given level relative to the voltage at said one input, said output of said comparator transitions to turn on said semiconductor switch, the output level of said comparator output being communicated back through said feedback connection to said one input of said comparator to change the switching threshold reference level back to said first mentioned given level, for repetition of the cycle.

In a heater assembly having a main burner intermittently ignited by an ignition system, a flame powered logic supply circuit responsive to the main burner flame and supplying electrical energy to charge a battery to power electronic logic circuitry for the heater assembly, said supply circuit comprising:

• a thermoelectric element responsive to said main burner flame and outputting electrical current;
• an electrical energy storage component connected to said thermoelectric element;
• a pair of parallel circuit branches connected to said thermoelectric element and said storage component,
• the first of said circuit branches including a semiconductor switch having an on state completing a circuit therethrough from said thermoelectric element such that current flow through said first circuit branch supplies energy to said storage component which is stored therein, said semiconductor switch having an off state blocking current flow in said first circuit branch such that current flow from said thermoelectric element flows through the second of said circuit branches,
• said second circuit branch including said battery receiving current from said thermoelectric element and from said storage component when said semiconductor switch is in said off state, to supply energy to said battery to maintain a given power rating thereof for powering said electronic logic circuitry of said heater assembly,
• monitoring circuitry monitoring the energy stored in said storage component and controlling said semiconductor switch between said on and off states to release said stored energy from said storage component to said battery during said off state of said semiconductor switch, and to re-supply energy to said storage component during said on state of said semiconductor switch.

In a heater assembly having a main burner intermittently ignited by an ignition system, a flame powered logic supply circuit responsive to the main burner flame and supplying electrical energy to power electronic logic circuitry for the heater assembly, said supply circuit comprising:

• a thermoelectric element responsive to said main burner flame and outputting electrical current, said thermoelectric element having first and second terminals;
• an inductor connected in series between said first terminal of said thermoelectric element and a first node;
• a current sensing resistor connected in series between said second terminal of said thermoelectric element and a second node;
• a semiconductor switch connected in series between said first and second nodes, said switch having a first terminal connected to said first node, a second terminal connected to said second node, and a control terminal for controlling conduction of said semiconductor switch between an on state conducting current between said first and second terminals of said semiconductor switch, and an off state blocking current flow between said first and second terminals of said semiconductor switch;
• a battery connected in series between said first and second nodes, and in parallel with said semiconductor switch;
• a comparator having an output connected to said control terminal of said semiconductor switch, a first input connected to said second terminal of said thermoelectric element, a second input connected to said second node, and a feedback connection between said output of said comparator and one of said inputs of said comparator,
• such that during said on state of said semiconductor switch, current flows from said thermoelectric element through said inductor through said semiconductor switch through said current sensing resistor and back to said thermoelectric element, said inputs of said comparator sensing the voltage across said resistor such that when the voltage at the other of said inputs reaches a first given level relative to the voltage at said one input, said output of said comparator transitions to turn off said semiconductor switch, the output level of said comparator being communicated back through said feedback connection to said one input of said comparator to change the switching threshold reference level thereat,
• and such that during said off state of said semiconductor switch, current flows from said thermoelectric element through said inductor through said battery through said current sensing resistor back to said thermoelectric element to transfer stored energy from said inductor to said battery during said off state of said semiconductor switch, such that said battery is charged by said current and is also charged by the energy previously stored in said inductor during the above noted previous on state of said semiconductor switch, to maintain a given power rating of said battery for powering said electronic logic circuitry of said heater assembly, said inputs of said comparator sensing the voltage across said resistor during said off state of said semiconductor switch such that when the voltage at said other input reaches a second given level relative to the voltage at said one input, said output of said comparator transitions to turn on said semiconductor switch, the output level of said comparator output being communicated back through said feedback connection to said one input of said comparator to change the switching threshold reference level back to said first mentioned given level, for repetition of the cycle.