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US 6,191,625 B1Granted
Balanced loss driver circuit including high-side/low-side MOS switches
AssigneeInfineon Technologies AG
InventorsFranz Wachter, Hubert Rothleitner, Johann Massoner
Life of this patent
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Abstract
A driver circuit having series-connected high-side and low-side MOS switches with MOS transistors for driving a load, a temperature-limiting circuit and a current-limiting circuit, which is assigned to one of the two MOS transistors. In order to balance power losses between the high-side and low-side MOS switches, provision is made for the gate of the MOS transistor without the current-limiting circuit to be connected to ground via a voltage generator, whose voltage corresponds to a maximum drive voltage for this MOS transistor.
Claims4
A driver circuit, comprising:
- a high-side MOS switch having a high-side MOS transistor with a gate for driving a load;
- a first temperature limiting circuit connected to said high-side MOS transistor;
- a low-side MOS switch having a low-side MOS transistor connected in series with said high-side MOS transistor for driving the load;
- a second temperature-limiting circuit connected to said low-side MOS transistor;
- a current-limiting circuit connected to said low-side transistor;
- and
- a Zener diode having a first side connected to said gate of said high-side MOS transistor and a second side connected to ground, said Zener diode outputting a voltage UZ corresponding to a maximum drive voltage for said high-side MOS transistor, said voltage UZ defined, at least approximately, as follows:
- U Z = U DD2 + I D R L 2 + U Tn + 2 I D β n
- where UDD2 is a drive voltage of said high-side MOS transistor connected to said Zener diode, ID is a drain current of said high-side MOS transistor, RL is a resistance of the load to be driven, UTn is a threshold voltage of said high-side MOS transistor, and βn is a gain of said high-side MOS transistor.
6 more elements
A driver circuit, comprising:
- a high-side MOS switch having a high-side MOS transistor for driving a load;
- a first temperature limiting circuit connected to said high-side MOS transistor;
- a current-limiting circuit connected to said high-side transistor;
- a low-side MOS switch having a low-side MOS transistor with a gate and connected in series with said high-side MOS transistor for driving the load;
- a second temperature-limiting circuit connected to said low-side MOS transistor;
- and
- a Zener diode having a first side connected to said gate of said low-side MOS transistor and a second side connected to ground, said Zener diode outputting a voltage UZ corresponding to a maximum drive voltage for said low-side MOS transistor, said voltage UZ defined, at least approximately, as follows:
- U Z = U DD2 + I D R L 2 + U Tn + 2 I D β n
- where UDD2 is a drive voltage of said low-side MOS transistor connected to said Zener diode, ID is a drain current of said low-side MOS transistor, RL is a resistance of the load to be driven, UTn is a threshold voltage of said low-side MOS transistor, and βn is a gain of said low-side MOS transistor.
6 more elements
Dependencies are inferred from the claim text.