CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority under 35 U.S.C. § 119 of European patent application no. 19306559.6, filed Dec. 3, 2019 the contents of which are incorporated by reference herein.

FIELD

The present invention relates to distributed interleaving control of multiphase switched mode power converters (SMPC). It more particularly relates to multiphase SMPCs, SMPCs modules, and controllers therefor. It further relates to methods of controlling such SMPC modules and multiphase SMPCs.

BACKGROUND

Multiphase switched mode power converters (SMPCs) are becoming increasingly important for a range of applications. They are in particular useful for systems which need to be robust against component failure: since the power is provided by a plurality of subunits, a fault or failure in one sub-unit may be compensated by suitably adjusting the remaining subunits. Conventionally, control of such multiphase SMPCs is provided by a central controller. However, such a controller can represent a further point of vulnerability in the system or a single point of failure (SPOF), and so recently, attention has been turning towards methods of providing distributed control which tend to reduce or minimise such single point of failure vulnerability. One such method is discussed by Cousineau et al in U.S. Pat. No. 9,608,450. However, there remains a need for simple and robust distributed control.

SUMMARY

According to a first aspect of the present disclosure, there is provided a controller for a switched mode power converter module for use in a multiphase switched mode power converter, the controller comprising: a signal generator, configured to generate a periodic signal, having a frequency and a signal phase and for controlling the switched mode power converter module, wherein the signal generator is further configured to generate a clock signal having the frequency and the signal phase; a first-clock input configured to receive a first-clock signal having the frequency and a first phase from a first neighbouring controller; and a second-clock input configured to receive a second-clock signal having the frequency and a second phase from a second neighbouring controller; wherein the signal generator comprises a phase adjustment circuit configured to adjust the phase of the periodic signal so as to be equidistant from the first and second phase, wherein the phase adjustment circuit comprises an error circuit configured to determine an error signal in dependence on an offset between the phase and a mid-point between the first phase and the second phase, and a feedback circuit configured to adjust the phase in dependence on the error signal.

The single bit digital or binary signal, which makes up the clock signal and which communicates between neighbouring modules is less prone to noise than is the analogue signals associated with known distributed control methodologies. This may improve the robustness of the design to noise, and may also simplify implementation.

In one or more embodiments the error circuit comprises digital logic for determining the error signal from a difference between a first value proportional to a phase deference between the signal phase and the first phase, and a second value proportional to a phase deference between the signal phase and the second phase. Digital logic may be particularly straightforward to implement.

In one or more embodiments the clock signal has a 50% duty cycle. The digital logic may comprise an exclusive or, XOR, combination of the signal clock and the first-clock signal to determine the first value, and an exclusive or, XOR, combination of the signal clock and the second-clock signal to determine the second value. These logical operations may enable a very simple and efficient determination of the error signal with minimal signal processing.

In one or more embodiments, the controller may further comprise a first clock output and a second clock output configured to, during normal operation, transmit the signal clock to first and second neighbouring controllers respectively. These clock signals may be used by the respective first and second neighbouring controllers in order to determine the appropriate phrase for their own clocks.

In one or more embodiments, the switched mode power converter module comprises at least one switch, and the controller further comprises a control module configured to control the at least one switch in dependence on the periodic signal. Thus the controller may comprise an interleaver which is separate from the control module, or the interleaver may be integral with the control module.

In one or more embodiments, the controller may further comprise a status indicator indicative of a status of the controller, and the controller may be further configured to, in response to the status indicator indicating that the controller is disabled, transmit the first-clock signal from the second clock output and transmit the second-clock signal from the first clock output. Provision of a status indicator to indicate whether the controller is disabled—either intentionally or possibly because of a fault in the associated module—may assist in simplifying the control in such circumstances.

According to a second aspect of the present disclosure is there is provided a switched mode power converter module comprising a controller as described above, at least one switch, and an inductive element, wherein the at least one switch is configured to switchably supply current to the inductive element, under the control of the controller.

In one or more embodiments, the SMPC module may further comprise a switch driver circuit connected to an output of the controller and to the or each control input of the at least one switch and adapted to drive the at least one switch. The switch driver circuit may be provided separately to the controller, and since in general higher currents and powers are required for drivers than the controllers, this may simplify the manufacture of the controller. The control and switch driver circuit may be provided packaged as a multichip module, or may be provided in separate chips.

According to a further aspect the present disclosure there is provided a multiphase switched mode power converter, comprising at least three switched mode power converter modules each described above, wherein the respective controllers are arranged in a daisy-chain configuration, and the phases of the respective clock signals are equally distributed. A daisy-chain configuration may also be referred to as a circular-chain configuration.

In one or more embodiments, the multiphase SMPC may comprise at least one further switched mode power converter module, wherein, in response the controller of the at least one further switched mode power converter module being disabled, the phases of the other switched mode power converter modules are equally distributed. The further switched mode power converter module may be in addition to the at least three switched mode power converter modules, in which case the other switched mode power converter module are the at least three switched mode power converter; alternatively, the further switched mode power converter module may be one of the at least three switched mode power converter modules, in which case the other switched mode power converter module are the remainder of the at least three switched mode power converter modules.

In one or more embodiments, the multiphase SMPC may comprise at least 6 switched mode power converter modules each as described above, arranged in a plurality of sub-groups, wherein the respective controllers within each sub-group are arranged in a daisy-chain configuration, and the phases of the respective clock signals within each sub-group are equally distributed. Thus, instead of a single daisy-chain, a more complex architecture may be appropriate for some applications. The phase of the clock signal of a one of the controllers, or where controllers are arranged in subgroups, the phase of the clock signal of one of the controllers for each sub-group, may be fixed.

According to yet further aspect of the present disclosure, there is disclosed a method of controlling a switched mode power converter module for use in a multiphase switched mode power converter, the method comprising: generating a periodic signal, having a frequency and a signal phase and for controlling the switched mode power converter module; generating a clock signal having the frequency and the signal phase; receiving a first-clock signal having the frequency and a first phase from a first neighbouring controller; and receiving a second-clock signal having the frequency and a second phase from a second neighbouring controller; adjusting the phase of the periodic signal, by means of a phase adjustment circuit, so as to be equidistant from the first and second phase, wherein adjusting the phase of the periodic signal comprises determining an error signal in dependence on an offset between the phase and a mid-point between the first phase and the second phase, adjusting the phase in dependence on the error signal by means of a feedback circuit.

There may be provided a computer program, which when run on a computer, causes the computer to configure any apparatus, including a circuit, controller, sensor, filter, or device disclosed herein or perform any method disclosed herein. The computer program may be a software implementation, and the computer may be considered as any appropriate hardware, including a digital signal processor, a microcontroller, and an implementation in read only memory (ROM), erasable programmable read only memory (EPROM) or electronically erasable programmable read only memory (EEPROM), as non-limiting examples. The software implementation may be an assembly program.

The computer program may be provided on a computer readable medium, which may be a physical computer readable medium, such as a disc or a memory device, or may be embodied as another non-transient signal.

These and other aspects of the invention will be apparent from, and elucidated with reference to, the embodiments described hereinafter.

