Techniques for reliably and efficiently generating an output voltage for use within an electronic device, such as a memory system, are disclosed. A voltage generation circuit generates the output voltage. The voltage generation circuit includes regulation circuitry that controls regulation of the output voltage to maintain the output voltage at a substantially constant level. According to one aspect, regulation is provided through use of different feedback circuits. By selectively disabling one of the feedback circuits, power consumption can be reduced and the other of the feedback circuits can support the continued regulation of the output voltage. The voltage generation circuit is therefore able to operate in an accurate, stable and power efficient manner.

Hybrid charge pump regulation

A single mode buck/boost charge pump has multiple outputs and is adapted to power a plurality of separate loads, such as light emitting diodes, in a highly efficient manner. The multiple outputs have different voltages. The output current or voltage of at least one of the multiple outputs is regulated by a feedback circuit. The feedback circuit provides a control signal based on a comparison of a reference voltage with a feedback voltage. The feedback voltage is proportional to an output voltage when the charge pump is configured to regulate the output voltage. Alternately, the feedback voltage is a sense voltage across a sense resistor connected in series with a load when the charge pump is configured to regulate output current provided to the load.

Multiple output charge pump

A multiple output regulating charge pump includes a load current regulator to balance currents in multiple branches of at least one load, such as light emitting diodes in a parallel configuration. The load current regulator includes current mirror circuits to provide substantially identical currents to the respective light emitting diodes, thereby producing uniform light from each of the light emitting diodes. The multiple output charge pump includes a charge storage component that is alternately charged during a charge cycle and discharged during a discharge cycle. The charge pump provides current to a second load during the charge cycle and to a first load during a discharge cycle.

Charge pump regulator with load current control

A multi-mode charge pump drive circuit has a multi-mode charge pump, a switch control circuit, a current regulation circuit, an error amplifier, a variable resistance unit, and a mode selection circuit. The multi-mode charge pump is operated with a plurality of modes, each of which provides a different multiplicative ratio for converting an input voltage source into a drive voltage. The switch control circuit applies a switch control signal to the multi-mode charge pump. The switch control signal has a slew rate of edge for determining a transition span of the interchange between charging and discharging phases. The mode selection circuit controls the multi-mode charge pump to selectively operate with one of the plurality of modes. When the mode selection circuit changes the mode of the multi-mode charge pump, the mode selection circuit applies a mode change signal to the switch control circuit so as to reduce the slew rate of edge.

Multi-mode charge pump drive circuit with improved input noise at a moment of mode change

A semiconductor integrated circuit has a central processing unit and a rewritable nonvolatile memory area disposed in an address space of the central processing unit. The nonvolatile memory area has a first nonvolatile memory area and a second nonvolatile memory area, which memorize information depending on the difference of threshold voltages. The first nonvolatile memory area has the maximum variation width of a threshold voltage for memorizing information set larger than that of the second nonvolatile memory area. When the maximum variation width of the threshold voltage for memorizing information is larger, since stress to a memory cell owing to a rewrite operation of memory information becomes larger, it is inferior in a point of guaranteeing the number of times of rewrite operation; however, since a read current becomes larger, a read speed of memory information can be expedited. The first nonvolatile memory area can be prioritized to expedite a read speed of the memory information and the second nonvolatile memory area can be prioritized in guaranteeing the number of times of rewrite operation of memory information more.

Semiconductor Integrated circuit

An improved charge pump circuit includes one switch element driven by a ramp
waveform to precisely control the output voltage. The circuit includes a switch group
(130) having one or more switch elements for transferring a charge to one or more
capacitors (C1), a feedback circuit having an error amplifier (126) for amplifying a
difference between a divided output voltage and a reference voltage (V ref), a
compensation circuit (131, 132) for phase compensating the feedback network, an
oscillator (127) for generating the ramp waveform, and a control circuit (128) for driving
the one or more switch elements. At least one of the switch elements has a resistance
that can be adjusted externally and is driven by the ramp waveform such that its
resistance varies with time. Accordingly, the charge transferred from a power source
(VDD) to the one or more capacitors (C1) can easily be adjusted. When the charge
transferred is small, the on-time of the ramp waveform is short and the average value of
the resistance is large. The average resistance of the switch group varies when the
voltage of the power source varies, so that an output with a fixed voltage and low ripple
voltage can be obtained.

Charge pump circuit

In an electronic circuit having a voltage supply means, a load means, and a regulating means, in order to limit the current flowing through a load, a supply voltage/current regulator is provided which comprises a voltage dividing circuit for dividing the supply voltage of a voltage supply, a reference voltage generator for generating a reference voltage, and a differential amplifier for comparing the divider output voltage and the reference voltage and for producing an output signal in accordance with the difference. The output signal is provided to the base of a transistor connected between the voltage supply and the load. The transistor is effective limit the current flow through the load such that the supply voltage does not decrease below a predetermined limit. By limiting the flow of current through the load such that the supply voltage does not decrease below a predetermined limit, the load may be driven continuously without the problem of lock-up common in ordinary voltage regulators. Thus, when the voltage source is a conventional battery, and the internal resistance of the battery increases due to the large load current or low ambient temperature, the load may nevertheless be driven continuously.

Supply voltage regulator and an electronic apparatus

PROBLEM TO BE SOLVED: To a voltage divider circuit for dividing an input voltage in accordance with a predetermined ratio with high accuracy, in which a source current does not flow from a voltage source and a sink current does not flow into the voltage source. SOLUTION: The voltage divider circuit includes: a constant current circuit for outputting a current flowing through a first resistor in accordance with to an input voltage as a constant current; a first current mirror circuit, in which the constant current becomes an input current, for outputting a first output current; a second current mirror circuit, in which the first output current becomes an input current, for outputting a second output current; and a second resistor connected to an output terminal to which the second output current of the second current mirror circuit is output, wherein a divided voltage, which is a potential difference between both ends of the second resistor, is adjusted by a current mirror ratio between the first current mirror circuit and the second current mirror circuit, and a resistance ratio between the second resistor and the first resistor. COPYRIGHT: (C)2010,JPO&INPIT

Voltage divider circuit

A switching transistor is arranged for charging a capacitor in response to a positive going transition of a clock signal. The charging time of the capacitor is determined by controlling the charging current in accordance with an input voltage to a transistor coupled to the capacitor. The pulse width of an output signal is dependent upon the charging time of the capacitor. Using the inventive pulse width modulator, by comparing the voltage of a reference voltage source with a divided voltage obtained through feedback of the output of the pulse width modulator, a switching power source is obtained by simply adding circuitry for converting, rectifying and smoothing the output voltage. A variable range of pulse width of up to 1800 times can be obtained. When the circuit is designed using complementary MOS devices, the operating voltage can be under 1V with a consumption current of less than several μA. When the circuit is integrated, the oscillator of the modulator and the oscillator of the electronic system in which the modulator is used can be easily switched, and the oscillators can be synchronized, resulting in a low noise, miniaturized switching power source.

Pulse duration modulator and pulse duration modulation type switching power source

PURPOSE:To stabilize the operation of an electronic system circuit by limiting the current flowing to a load circuit which drives a driving element consuming a large current and preventing the source voltage from dropping below a specific voltage level. CONSTITUTION:An arithmetic circuit 4 compares the output Vc of voltage detecting circuits R1 and R2 detecting the voltage of a battery 1 with the reference voltage Vd of a reference voltage generating circuit 6 and a transistor circuit 5 is controlled with the output voltage of the arithmetic circuit 4 to limit the current flowing from the battery to the load circuit 7. Consequently, even if a large load current flows, the electronic system circuit can be placed in stable operation.

Kimio Shibata

Papers

Charge pump circuit

Supply voltage regulator and an electronic apparatus

Voltage divider circuit

Pulse duration modulator and pulse duration modulation type switching power source

Source voltage adjusting circuit and electronic device using the same