KCC Quizzes AQQ303 about the radius of a circle
1. Quote of the month: "When I die, I want to die like my grandfather who died peacefully in his sleep. Not screaming like all the passengers in his car" - Will Rogers
2. Quiz AQQ304 about finding the radius of a circle
Good luck, and try to be
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August Monthly Blog Quiz! Read the blog, take the quiz, and you could win a gift card
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Stay in the loop and win! Read the blog Current Output Driving Industrial Loops , then take our quick five-question quiz for a chance to win a gift card
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LT1158
Production
A single input pin on the LT1158 synchronously controls two N-channel power MOSFETs in a totem pole configuration. Unique adaptive protection against shoot...
Datasheet
LT1158 on Analog.com
I was looking for leads on H-bridge design and I noticed a curious thing: in some example circuits for the LT1158 (like the Figure 17. 10A Full Bridge Motor Control at page 20 of the datasheet or Figure 171. H-Bridge Motor Driver with Ground Referenced Current Sensing in AN66) the high side gate driver outputs have clamp diodes toward ground. (D1 and D2 at page 20). I guess it's only for full bridge DC motor control since other examples don't use these.
What are these diodes for? My first guess is transient protection like the common source under ground transient (coupled through parasitics to the gate), but that is usually solved clamping the source to ground, not the gate. Maybe it's because the DC motor is a highly inductive *and* a generator too?
Is that protection specific to the 1158 topology (since it has no high voltage tub) or it can be applied more generally to other drivers?
I can't find in literature any reference
Thanks in advance
Hi lomarcan,
I believe this is protection for negative transients that may cause early tripping.

Hi lomarcan,
I believe this is protection for negative transients that may cause early tripping.
