Switching converter with several converter stages

• US 20070236287A1
• Filed: 03/23/2007
• Published: 10/11/2007
• Est. Priority Date: 03/23/2006
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Bernacchia, Giuseppe, Pittassi, Riccardo
• Granted Patent: US 7,759,919 B2
• Time in Patent Office: Days
• US Class Current: 330/10
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

The invention relates to a switching converter for generating an output voltage (Vout) from an input voltage (vin), comprising:

• a control arrangement (30) for furnishing a control signal (Serr) dependent on the output voltage (Vout);
• a first converter stage (1A) and at least one second converter stage (1B, 1C), each of which has: an inductive storage element (11A, 11B, 11C), a current measurement arrangement (12A, 12B, 12C) which is designed to detect a current (IL1, IL2, IL3) across the inductive storage element (11A, 11B, 11C) and to furnish a current measuring signal (Is1, Is2, Is3) proportional to this current, a pulse width modulator (16A, 16B, 16C) which receives the control signal (Serr) and the current measuring signal (Is1, Is2, Is3) and which furnishes a pulse width modulated signal (PWM1, PWM2, PWM3), and a driver circuit which receives the pulse width modulated signal (PWM1, PWM2, PWM3) and the input voltage (Vin) and which applies the input voltage (Vin) in dependence on the pulse width modulated signal (PWM1, PWM2, PWM3) to the inductive storage element (11A, 11B, 11C), wherein
• a proportionality factor between the current (IL2, IL3) across the inductive storage element (11B, 11C) and the current measuring signal (Is2, Is3) of the current measurement arrangement (12B, 12C) of the at least one second converter stage (1B, 1C) can be adjusted and wherein
• the current measurement arrangement (12B, 12C) of the at least one second converter stage receives an adjustment signal (k2, k3), which is dependent on a proportionality factor between a current across the inductive storage element (11A) of the first switching converter (1A) and the current measuring signal (Is1) of the first switching converter (1A).

Claims

1. Switching converter for generating an output voltage (Vout) from an input voltage (vin), comprising:

a control arrangement (30) for furnishing a control signal (Serr) dependent on the output voltage (Vout),

a first converter stage (1A) and at least one second converter stage (1B, 1C), each of which has;

an inductive storage element (11A, 11B, 11C), a current measurement arrangement (12A, 12B, 12C) which is designed to detect a current (IL1, IL2, IL3 ) across the inductive storage element (11A, 11B, 11C) and to furnish a current measuring signal (Is1, Is2, Is3) proportional to this current, a pulse width modulator (16A, 16B, 16C) which receives the control signal (Serr) and the current measuring signal (Is1, Is2, Is3) and which furnishes a pulse width modulated signal (PWM1, PWM2, PWM3), and a driver circuit which receives the pulse width modulated signal, (PWM1, PWM2, PWM3) and the input voltage (Vin) and which applies the input voltage (Vin) in dependence on the pulse width modulated signal (PWM1, PWM2, PWM3) to the inductive storage element (11A, 11B, 11C), wherein

a proportionality factor between the current (IL2, IL3) across the inductive storage element (11B, 11C) and the current measuring signal (Is2, Is3) of the current measurement arrangement (12B, 12C) of the at least one second converter stage (1B, 1C) can be adjusted and wherein

the current measurement arrangement (12B, 12C) of the at least one second converter stage receives an adjustment signal (k2, k3), which is dependent on a proportionality factor between a current across the inductive storage element (11A) of the first switching converter (1A) and the current measuring signal (Is1) of the first switching converter (1A).

2. Switching converter according to claim 1, in which the current measurement arrangements (12A, 12B, 12C) each have a measuring amplifier (14A, 14B, 14C) connected to the current measuring resistor (13A, 13B, 13C).

3. Switching converter according to claim 2, in which a gain of the measuring amplifier (14B, 14C) of the current measurement arrangement of the at least one second converter stage (1B, 1C) can be adjusted and in which this measuring amplifier (14B, 14C) receives the adjustment signal (k3, k4).

4. Switching converter according to one of the foregoing claims, in which the current measuring resistor (13A, 13B, 13C) is connected in series with the inductive energy storage element (11A, 11B, 11C).

5. Switching converter according to one of the foregoing claims, in which the driver circuits (15A, 15B, 15C) each have a switch element (151), which is actuated by the pulse width modulated signal (PWM).

6. Switching converter according to claim 4 and 5, in which the switch element (151) is a semiconductor switch element with a turn-on resistance and in which the semiconductor switch element (151) serves as the current measuring resistor.

7. Switching converter according to one of claims 1 to 3, in which the current measurement arrangements each have a current mirror (131) which is coupled to a current pathway with the inductive storage element (11) and to the current measuring resistor (13 ) and which is designed to copy a current (IL) flowing through the inductive storage element onto a measuring current (IM) flowing through the measuring resistor (13).

8. Switching converter according to one of the foregoing claims, having a calibration circuit which furnishes the adjustment signal for the at least one second switching converter.

9. Switching converter for generating an output voltage (Vout) from an input voltage (Vin), comprising:

a control arrangement (30) for furnishing a control signal (Serr) dependent on the output voltage (Vout),

a first converter stage (1A) and at least one second converter stage (1B, 1C), each of which have;

an inductive storage element (11A, 11B, 11C) with an inductance (L1, L2, L3), a ramp signal generator (19A, 19B), designed to provide a ramplike signal (Sr) having a ramp slope, a pulse width modulator (16A, 16B, 16C) which receives the control signal (Serr) and the ramplike signal and which furnishes a pulse width modulated signal (PWM1, PWM2, PWM3), and a driver circuit which receives the pulse width modulated signal (PWM1, PWM2, PWM3) and the input voltage (Vin) and which applies the input voltage (Vin) in dependence on the pulse width modulated signal (PWM1, PWM2, PWM3) to the inductive storage element (11A, 11B, 11C), wherein

a ramp slope of the ramp signal generator (19B, 19C) of the at least one second converter stage (1B, 1C) can be adjusted and wherein

the ramp signal generator (19B, 19C) of the at least one second converter stage receives an adjustment signal (k2, k3) which is dependent on the inductance of the inductive storage element of the first converter stage (1A).