Programmable load transient compensator for reducing the transient response time to a load capable of operating at multiple power consumption levels

Abstract

A load transient compensator and method of operating the load transient compensator for reducing the transient response time to a load capable of operating at either of several consumption levels when the load changes its power consumption level . The load transient compensator has a comparator having an output connected to an input of an upper driver and of a lower driver with the output of each of the driver being connected to a gate of a power transistor. When the load is in sleep mode and is about to start being accessed, the upper driver is turned on to turn on its associated transistor to supply additional current to the load, regulated by the comparison circuit. When the load is in the power up mode and it is about to stop being accessed, the lower driver is turned on to turn on its associated transistor to drain current supplied to the load by a supply, regulated by the comparison circuit. This allows a quicker response to the large changes in current required by the load when the load is changing its level of power consumption without greatly increasing the cost of the system containing the load and without compromising the stability of the system.

Description

TECHNICAL FIELD[0001]The present invention relates to the field of integrated circuits, and is more specifically directed to circuits for reducing the transient response time of a system in delivering required voltage to a load.BACKGROUND[0002]In order to reduce power consumption many electronic components are now capable of operating at several power consumption levels, one of which is typically a power-down or sleep mode. The power-down mode is a low power consumption level that the component can enter into when it is not performing an operation and not being accessed. Reducing the level of power consumption is particularly useful for battery operated devices, such as portable computers, where reducing power consumption increases the battery life, and therefore the time the device can be used without having to either replace or recharge the battery.[0003]A microprocessor consumes a significant amount of power in the full power-up mode, and it is typically accessed only a small por...

AI Technical Summary

Benefits of technology

[0007]According to principles of the present invention, a load transient compensator is provided to reduce the transient response time of a system. The load transient compensator has a power supply input terminal, a control input terminal for coupling to a control circuit, and an output terminal for coupling to a power supply input terminal of a load. The control circuit has an access signal input terminal, a first control output terminal coupled to the load, and a second control output terminal coupled to the control input terminal of the load transient compensator.

[0009]The load transient compensator allows a quick response to the large changes in current required by the load when the load is changing its level of power consumption, accomplished without greatly increasing the cost of the system containing the load and without compromising the stability of the system.

Problems solved by technology

The large change in current demand of the microprocessor, which is the load of the system, may bring the system out of regulation during the transient response.

A problem with the above methods is that during the time that the change in current demand is going through the feedback loop, or by the time the monitoring circuit detects that the current demand of the load has changed, the load is not receiving the appropriate voltage.

The present inventor has observed that another problem with the above method is that during the time it takes to detect the change in the current demand the load is not receiving the proper voltage due to the large current demand, the voltage regulator does not know that it is not delivering the required voltage and has not even changed its bandwidth, thus increasing the transient response time by this amount of time.

Another problem with switching the frequency of the voltage regulator is that in order to get the required voltage quickly enough the frequency during the transient response has to be very high, typically on the order of 500 kHz or more.

This requires high performance components, which are typically complicated and expensive.

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