Single inductor multiple output (SIMO) direct current-to-direct current (DC/DC) converter and control method thereof

Patent metadata

Field	Value
Publication number	US-9007039-B2
Application number	US-201213495382-A
Country	US
Kind code	B2
Filing date	Jun 13, 2012
Priority date	Dec 13, 2011
Publication date	Apr 14, 2015
Grant date	Apr 14, 2015

Abstract

Provided is a single inductor multiple output (SIMO) direct current-to-direct current (DC/DC) converter that may perform DC/DC conversion by transferring, to output nodes, input current that is input and thereby stored in a single inductor. An output selection unit of the SIMO DC/DC converter may select, from output nodes, a first output node to be supplied with current from a driving unit, and provide output voltage of the first output node and reference voltage of the first output node to a hysteresis comparison unit. The hysteresis comparison unit may control on-time and/or inductor peak current by determining whether the output voltage of the first output node is higher than the reference voltage of the first output node by at least a first threshold, and whether the output voltage of the first output voltage is lower than the reference voltage of the first output voltage by at least a second threshold.

First claim

What is claimed is:

1. A converter, comprising:
an output selection unit to select, from a plurality of output nodes, a first output node to be supplied with current from a driving unit;
a comparison unit to determine whether an output voltage of the first output node is higher than a reference voltage of the first output node by comparing the output voltage of the first output node with the reference voltage of the first output node; and
a control unit to adjust a first time length to be a maximum time length in which the current is continuously supplied to the first output node based on the determination result,
wherein the control unit comprises:
an on-time controller to increase the first time length when a counted number of current supplies exceeds a maximum number of current supplies; and
an inductor peak current controller to control a peak value of input current.

2. The converter of claim 1 , wherein the comparison unit is a hysteresis comparison unit to determine whether the output voltage of the first output node is higher than the reference voltage of the first output node by at least a first threshold, and to determine whether the output voltage of the first output voltage is lower than the reference voltage of the first output voltage by at least a second threshold.

3. The converter of claim 2 , wherein the comparison unit comprises:
a first RS flip-flop corresponding to the first output node;
a first comparator to compare the output voltage of the first output node with a voltage higher than the reference voltage of the first output node by the first threshold;
a second comparator to compare the output voltage of the first output node with a voltage lower than the reference voltage of the first output voltage by the second threshold; and
at least one multiplexer to transfer an output value of the first comparator and an output value of the second comparator to the first RS flip-flop, and
the first RS flip-flop stores the output value of the first comparator and the output value of the second comparator.

4. The converter of claim 3 , wherein the first RS flip-flop transfers the output value of the first comparator and the output value of the second comparator to the control unit to count the number of current supplies to which current is supplied by the control unit to the first output node until the output value of the first comparator becomes to be higher than the reference voltage of the first output node by the first threshold after the output voltage of the first output node is lower than the reference voltage of the first output node by at least the second threshold.

5. The converter of claim 3 , wherein the control unit comprises:
a counter to count the number of current supplies to which current is supplied by the control unit to the first output node until the output value of the first comparator becomes to be higher than the reference voltage of the first output node by the first threshold after the output voltage of the first output node is lower than the reference voltage of the first output node by at least the second threshold; and
a number of rising (NR) comparator to compare the counted number of current supplies with a predetermined maximum number of current supplies.

6. The converter of claim 5 , wherein:
when the first time length exceeds a first maximum time length set with respect to the first output node by increasing the first time length, the on-time controller provides an instruction signal instructing to increase a peak value of input current that is input to the driving unit, without increasing the first time length,
wherein the inductor peak current controller controls the peak value of input current to increase by transferring the instruction signal to the driving unit.

7. The converter of claim 5 , wherein:
the NR comparator compares the counted number of current supplies with a predetermined minimum number of current supplies, and
the on-time controller is set to decrease the first time length when the counted number of current supplies is less than the minimum number of current supplies.

8. The converter of claim 7 , wherein:
when the first time length becomes to be less than a first minimum time length set with respect to the first output node by decreasing the first time length, the on-time controller provides an instruction signal instructing to decrease a peak value of input current that is input to the driving unit, without decreasing the first time length, and
wherein the inductor peak current controller controls the peak value of input current to decrease by transferring the instruction signal to the driving unit.

9. A single inductor multiple output (SIMO) direct current-to-direct current (DC/DC) converter, comprising:
a driving unit to store input current that is received from a single input node during a charging time duration and to transfer the stored input current to a plurality of output nodes during a discharging time duration;
a load switch controller to supply current to a first output node among the plurality of output nodes during a first time length corresponding to the first output node within the discharging time duration, wherein the current is transferred by the driving unit;
a comparison unit to compare an output voltage of the first output node with a reference voltage corresponding to the first output node;
an on-time controller to increase the first time length when a counted number of current supplies exceeds a maximum number of current supplies; and
an inductor peak current controller to control the peak value of input current.

10. The SIMO DC/DC converter of claim 9 , wherein the SIMO DC/DC converter is a hysteresis comparison unit to determine whether the output voltage of the first output node is higher than the reference voltage of the first output node by at least a first threshold, and to determine whether the output voltage of the first output voltage is lower than the reference voltage of the first output voltage by at least a second threshold.

11. The SIMO DC/DC converter of claim 9 , wherein the controller comprises:
a counter to count the number of current supplies to which current is supplied by the controller to the first output node until an output value of a first comparator becomes to be higher than the reference voltage of the first output node by a first threshold after the output voltage of the first output node is lower than the reference voltage of the first output node by at least a second threshold;
a number of rising (NR) comparator to compare the counted number of current supplies with a predetermined maximum number of current supplies or a predetermined minimum number of current supplies; and
the on-time controller decreases the first time length when the counted number of current supplies is less than the minimum number of current supplies.

12. The SIMO DC/DC converter of claim 11 , wherein when the first time length exceeds a first maximum time length set with respect to the first output node by increasing the first time length when the counted number of current supplies exceeds the maximum number of current supplies, the on-time controller provides an instruction signal instructing to increase a peak value of input current that is input to the driving unit without increasing the first time length,
the inductor peak current controller controls the peak value of input current to increase by transferring the instruction signal to the driving unit.

13. The SIMO DC/DC converter of claim 11 , wherein when the first time length becomes to be less than a first minimum time length set with respect to the first output node by decrea

Assignees

• Kim Chul Woo
• Kim Jung Moon
• Univ Korea Res & Bus Found

Inventors

• Kim Chul Woo
• Kim Jung Moon

Classifications

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02M2001/009

  Electricity · mapped topic

• H02M3/155 Primary

  using semiconductor devices only · CPC title

• H02M1/009

  having two or more independently controlled outputs (for DC-DC converter with intermediate AC H02M3/33561) · CPC title