Monitoring circuit for a supply voltage
AssigneeSchneider Automation Inc.
InventorsRainer Horstkotte, Thomas Bierwirth
Life of this patent
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Abstract
The invention relates to a monitoring circuit for at least one supply voltage (UB, UH), including a first threshold switch (20), which if the supply voltage (UB) drops below a predeterminable threshold value generates a first warning signal (USWN), and a second threshold switch (66), which after a fixed warning period tw elapses generates a second warning signal (TOTUSN). In order that the warning signals will be generated without bounce, it is provided that the threshold switches (20, 66) each have an internal counting circuit for determining time periods tv1, tv2, after which the first and second warning signals (USWN, TOTUSN) generated are reset.
Claims16
A monitoring circuit (10) for at least one supply voltage (UB), comprising:
- a first threshold switch means (20), which generates a first warning signal (USWN) when the supply voltage (UB) drops below a first predetermined threshold value;
- a second threshold switch means (66), which generates a second warning signal (TOTUSN) after a fixed warning period tw has elapsed;
- each of the threshold switch means (20, 66) include an internal counting circuit for determining first and second time periods tv1, tv2;
- said first and said second generated warning signal (USWN, TOTUSN) is reset at the end of said first and second time periods.
A monitoring circuit for at least one supply voltage (UB), including a first threshold switch (20), which if the supply voltage (UB) drops below a predeterminable threshold values generates a first warning signal (USWN);
- a second threshold switch (66) which after a fixed warning time tw generates a second warning signal (TOTUSN);
- each of the threshold switches (20, 66) have an internal counting circuit for determining time periods tv1, tv2, after which the first and second warning signals (USWN, TOTUSN) generates are reset;
- the first threshold switch (20) is followed by a capacitor (40) which is discharged as a reaction to the first warning signal (USWN) and is recharged as a reaction to the second warning signal (TOTUSN);
- the capacitor (40) is connected by its positive terminal, via resistor (38) and a transistor (36), to a positive pole of the supply voltage, and by its negative terminal to a negative pole of the supply voltage;
- and the capacitor (40) is connected by its positive terminal to the input (68) of the threshold switch (66).
A monitoring circuit for at least one voltage, including a first threshold switch (20), which if the voltage drops below a predeterminable threshold value, generates a first warning signal (USWN);
- a second threshold switch (66) which after a fixed warning time tw generates a second warning signal (TOTUSN);
- the threshold switches (20, 66) each have an internal counting circuit for determining time periods tv1, tv2, after which the first and second warning signals (USWN, TOTUSN) generates are reset;
- the first threshold switch (20) is followed by a capacitor (40) which is discharged as a reaction to the first warning signal (USWN) and is recharged as a reaction to the second warning signal (TOTUSN);
- the capacitor (40) is connected by its positive terminal, via resistor (38) and a transistor (36), to a positive pole of the auxiliary voltage (UH), and by its negative terminal to a negative pole of the auxiliary voltage (UH);
- and the capacitor (40) is connected by its positive terminal to the input (68) of the threshold switch (66).
Dependencies are inferred from the claim text.