Controller and control method for DC-DC converter
First Claim
1. A DC-DC converter comprising:
- a first transistor receiving input voltage;
a second transistor coupled in series to the first transistor; and
a controller controlling the first transistor and the second transistor to select either one of a first mode in which the DC-DC converter operates as a switching regulator and a second mode in which the DC-DC converter operates as a linear regulator,wherein output voltage and output current changing in accordance with the output voltage are generated through a node between the first transistor and the second transistor, andwherein the controller includes a mode control circuit which monitors the input voltage, the output voltage, and the output current, the mode control circuit including;
a multiplier which determines a load current in which efficiency of the switching regulator and efficiency of the linear regulator are substantially the same based on a consumption current consumed in the controller, a monitored input voltage and a monitored output voltage, anda comparator which compares the load current with a monitored output current, and generates a mode control signal for selecting the one of the first mode and the second mode based on a comparing result.
9 Assignments
0 Petitions
Accused Products
Abstract
A DC-DC converter having conversion efficiency that is not lowered by input voltage change. A mode control circuit of the DC-DC converter monitors the input voltage, output voltage generated from the input voltage, and output current. The output current changes in accordance with the output voltage. Based on the input voltage, output voltage, and consumption current of a controller of the DC-DC converter, the mode control circuit generates a signal that is in accordance with load current in which efficiency of a switching regulator and efficiency of a linear regulator are substantially the same. The mode control circuit further compares a signal corresponding to the output current and the signal that is in accordance with the load current to generate a mode control signal. The controller operates the DC-DC converter as the switching regulator or the linear regulator in accordance with the mode control signal.
64 Citations
17 Claims
-
1. A DC-DC converter comprising:
-
a first transistor receiving input voltage; a second transistor coupled in series to the first transistor; and a controller controlling the first transistor and the second transistor to select either one of a first mode in which the DC-DC converter operates as a switching regulator and a second mode in which the DC-DC converter operates as a linear regulator, wherein output voltage and output current changing in accordance with the output voltage are generated through a node between the first transistor and the second transistor, and wherein the controller includes a mode control circuit which monitors the input voltage, the output voltage, and the output current, the mode control circuit including; a multiplier which determines a load current in which efficiency of the switching regulator and efficiency of the linear regulator are substantially the same based on a consumption current consumed in the controller, a monitored input voltage and a monitored output voltage, and a comparator which compares the load current with a monitored output current, and generates a mode control signal for selecting the one of the first mode and the second mode based on a comparing result. - View Dependent Claims (2, 3, 4, 5, 15)
-
-
6. A controller for a DC-DC converter including a first transistor receiving input voltage and a second transistor coupled in series to the first transistor, the controller comprising:
-
a circuit controlling the first transistor and the second transistor to select either one of a first mode in which the DC-DC converter operates as a switching regulator and a second mode in which the DC-DC converter operates as a linear regulator, wherein output voltage and output current changing in accordance with the output voltage are generated through a node between the first transistor and the second transistor, and wherein the circuit includes a mode control circuit which monitors the input voltage, the output voltage, and the output current, the mode control circuit including; a multiplier which determines a load current in which efficiency of the switching regulator and efficiency of the linear regulator are substantially the same based on a consumption current consumed in the controller, a monitored input voltage and a monitored output voltage, and a comparator which compares the load current with a monitored output current, and generates a mode control signal for selecting the one of the first mode and the second mode based on a comparing result. - View Dependent Claims (7, 8, 9, 10, 16)
-
-
11. A method for controlling a DC-DC converter that includes a first transistor receiving input voltage, a second transistor coupled in series to the first transistor, and a controller which controls the first transistor and the second transistor to select either one of a first mode in which the DC-DC converter operates as a switching regulator and a second mode in which the DC-DC converter operates as a linear regulator, wherein output voltage and output current changing in accordance with the output voltage are generated through a node between the first transistor and the second transistor, the method comprising:
-
monitoring the input voltage, the output voltage, and the output current; determining a load current in which efficiency of the switching regulator and efficiency of the linear regulator are substantially the same based on a consumption current to be consumed in the controller, a monitored input voltage, and a monitored output voltage; comparing the load current with a monitored output current; and based on a comparing result, generating a mode control signal for selecting one of the first mode and the second mode. - View Dependent Claims (12, 13, 14, 17)
-
Specification