US 8,013,642 B2Granted

Output drive circuit

AssigneeRenesas Electronics Corporation

InventorKurao Nakagawa

Life of this patent

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Abstract

An output drive circuit includes: a totem-pole output including: a high-side transistor (HST) with drain and source, an output stage power supply voltage applied to the drain, the source connected to the first node (N1); and a low-side transistor with source and drain, a ground voltage applied to the source, the drain connected to N1; and a bootstrap part including a capacitor supplying charge to a gate of HST when on, the charge being charged when HST is off, and one terminal of the bootstrap part connected to N1, the output drive circuit further including: a first transistor (T1) that conducts when HST is to be on, T1 connected between a drive circuit power supply voltage and the gate of HST; and a second transistor conducting when HST is to be turned on, the second transistor connected between the other terminal of the capacitor and HST gate.

Claims18

Dependent claims

An output drive circuit comprising:

a totem-pole-type output part that drives a load connected to a first node, the totem-pole-type output part comprising:
a high-side transistor with a drain and a source, an output stage power supply voltage being applied to the drain, and the source being connected to the first node;
and
a low-side transistor with a source and a drain, a ground voltage being applied to the source, and the drain being connected to the first node;
and
a bootstrap part comprising a capacitive element that supplies electrical charge to a gate of the high-side transistor when the high-side transistor is in an On-state, the electrical charge being charged when the high-side transistor is in an Off-state, and one terminal of the bootstrap part being connected to the first node,
the output drive circuit further comprising:
a first switch that becomes a conductive state when the high-side transistor is to be turned on, the first switch being connected between a drive circuit power supply voltage and the gate of the high-side transistor;
and
a second switch that becomes a conductive state when the high-side transistor is to be turned on, the second switch being connected between the other terminal of the capacitive element and the gate of the high-side transistor,
wherein the first switch includes a first transistor and the second switch includes a second transistor, and
wherein the first transistor constitutes a current mirror using a third transistor as an input-side transistor, and feeds a current according to a current flowing the third transistor when in a conductive state.

9 more elements

An output drive circuit comprising:

a drive circuit power supply voltage node;
an output stage power supply voltage node;
a totem-pole-type output part that drives a load connected to a first node, the totem-pole-type output part comprising i) a high-side transistor with a drain and a source, the drain of the high-side transistor connected to the output stage power supply voltage node, and the source of the high-side transistor connected to the first node;
and ii) a low-side transistor with a source and a drain, the source of the low-side transistor connected to a ground voltage node, and the drain of the low-side transistor connected to the first node;
a bootstrap part comprising a capacitive element that supplies electrical charge to a gate of the high-side transistor when the high-side transistor is in an On-state, the electrical charge being charged when the high-side transistor is in an Off-state, one terminal of the capacitive element being connected to the first node;
a first switch that becomes a conductive state when the high-side transistor is to be turned on, the first switch having a source connected to the drive circuit power supply voltage node and having a drain connected to the gate of the high-side transistor;
and
a second switch that becomes a conductive state when the high-side transistor is to be turned on, the second switch having a source connected the other terminal of the capacitive element and a drain connected to the gate of the high-side transistor.

5 more elements

An output drive circuit comprising:

an output stage power supply voltage node;
an input stage power supply voltage node,
a totem-pole-type output part that drives a load connected to a first node, the totem-pole-type output part comprising i) a high-side transistor with a drain and a source, the drain of the high-side transistor connected to the output stage power supply voltage node, and the source of the high-side transistor connected connected to the first node, and ii) a low-side transistor with a source and a drain, the source of the low-side transistor connected to a ground voltage node, and the drain of the low-side transistor connected to the first node;
a bootstrap part comprising a capacitive element that supplies electrical charge to a gate of the high-side transistor when the high-side transistor is in an On-state, the electrical charge being charged when the high-side transistor is in an Off-state, a first terminal of the capacitive element being connected to the first node, a second terminal of the capacitive element being connected to one of the output stage power supply voltage node and the input stage power supply voltage node;
a first switch that becomes a conductive state when the high-side transistor is to be turned on, the first switch having a first element connected to the drive circuit power supply voltage node and having a second element connected to the gate of the high-side transistor;
and
a second switch that becomes a conductive state when the high-side transistor is to be turned on, the second switch having a first element connected the second terminal of the capacitive element and a second element connected to the gate of the high-side transistor.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/478,067Filed 4 Jun 2009
Priority: JP 2008-15869018 Jun 2008
Published: US 2009/0315595 A124 Dec 2009
Granted: 6 Sep 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H03K 19/018571
Coupling arrangements; Impedance matching circuits: of complementary type, e.g. CMOS
H03K 17/063
Modifications for ensuring a fully conducting state: in field-effect transistor switches
H03K 2217/0081
Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00: power supply means, e.g.…
H03K
Pulse technique