Output stage having zener voltage balancing
AssigneeRobert Bosch GmbH
InventorsUwe Lueders, Juergen Eckhardt, Bernd Mueller
Life of this patent
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Abstract
An output stage, especially a switching output stage for switching inductive loads, having a plurality of individual output stages that are connected in parallel, which include degenerative transistors, in the degenerative path of which one respective Zener diode is present. The electric power during a switching-off process can be distributed in a particularly uniform manner to the individual output stages or transistors by disposing the Zener diodes near the associated transistors so that they are thermally coupled to the respectively associated transistor and their Zener voltage increases with increasing temperature.
Claims15
A switching output circuit for switching inductive or ohmic inductive loads, comprising:
- a plurality of output stages connected in parallel, each output stage having at least one Zener diode having a Zener voltage, and a switching transistor,
- wherein the at least one Zener diode in a first output stage is situated in or at such a proximity to the switching transistor of the first output stage that heat generated by a current going through the switching transistor of the first output stage increases the Zener voltage of the at least one Zener diode in the first output stage, and wherein the Zener voltage of the at least one Zener diode in the first output stage is increased to a same level of the Zener voltage of the at least one Zener diode in a second output stage to cause the at least one Zener diode in the second output stage to conduct a current.
Dependencies are inferred from the claim text.