Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
187 words
A substrate voltage generator in a semiconductor device having a voltage down converter for stepping down an externally applied power supply voltage to a prescribed voltage and generating an internal stepped-down power supply voltage, said semiconductor device being formed on a semiconductor substrate, said substrate voltage generator comprising: first substrate voltage applying means operating with said externally applied power supply voltage as an operation power supply voltage for applying a first bias voltage to said semiconductor substrate; second substrate voltage applying means operating with said internal stepped-down power supply voltage as an operation power supply voltage for applying a second bias voltage to said semiconductor substrate; substrate potential detecting means for detecting a potential of said semiconductor substrate; first selective activation means responsive to an output of said substrate potential detecting means for selectively activating said first and second substrate voltage applying means; stable state detecting means for detecting whether said internal stepped-down voltage is in a stable state or not, and second selective activation means responsive to an output of said stable state detecting means for selectively activating said first and second substrate voltage applying means.
Claim 2
Dependent Claim
187 words
A substrate voltage generator in a semiconductor device having a voltage down converter for stepping down an externally applied power supply voltage to a prescribed voltage and generating an internal stepped-down power supply voltage, said semiconductor device being formed on a semiconductor substrate, said substrate voltage generator comprising: first substrate voltage applying means operating with said externally applied power supply voltage as an operation power supply voltage for applying a first bias voltage to said semiconductor substrate; second substrate voltage applying means operating with said internal stepped-down power supply voltage as an operation power supply voltage for applying a second bias voltage to said semiconductor substrate; substrate potential detecting means for detecting a potential of said semiconductor substrate; first selective activation means responsive to an output of said substrate potential detecting means for selectively activating said first and second substrate voltage applying means; stable state detecting means for detecting whether said internal stepped-down voltage is in a stable state or not, and second selective activation means responsive to an output of said stable state detecting means for selectively activating said first and second substrate voltage applying means.
Claim 3
Dependent Claim
67 words
The generator in accordance with claim 1, wherein said stable state detecting means includes power supply voltage application detecting means for detecting application of said externally applied power supply voltage to said semiconductor device, and control signal generating means responsive to an output of said power supply voltage application detecting means for generating a control signal and applying the control signal to said second selective activation means.
Claim 4
Dependent Claim
86 words
The generator in accordance with claim 2, wherein said control signal generating means includes first control signal generating means responsive to an output from said power supply voltage application detecting means for generating a first control signal activating said first substrate voltage applying means in a prescribed period, and second control signal generating means responsive to the output from said power supply voltage application detecting means for generating a second control signal activating said second substrate voltage generating means after an elapse of said prescribed period.
Claim 5
Dependent Claim
33 words
The generator in accordance with claim 1, wherein said stable state detecting means includes thresholding means for thresholding said internal stepped-down voltage and applying the thresholded voltage to said second selective activation means.
Claim 6
Dependent Claim
110 words
The generator in accordance with claim 1, wherein said voltage down converter includes a reference voltage generating circuit responsive to said externally applied power supply voltage for generating a predetermined reference voltage, a comparator comparing said internal stepped-down voltage and said reference voltage and generating a regulation signal according to a result of the comparison, and an output circuit responsive to said regulation signal for converting said externally applied power supply voltage to said internal stepped-down voltage and outputting said internal stepped-down voltage, and said stable state detecting means includes said comparator, with said regulation signal being supplied to said second selective activation means as a selective activation control signal.
Claim 7
Dependent Claim
103 words
The generator in accordance with claim 1, wherein said first and second substrate voltage applying means include in common a ring oscillator including a plurality of cascade-connected inverters, and a charge pump circuit responsive to an output of said ring oscillator for generating a bias voltage by a charge pump function and applying the bias voltage to said semiconductor substrate, and said second selective activation means includes means responsive to an output of said stable state detecting means for selectively supplying either said externally applied power supply voltage or said internal stepped-down voltage to said ring oscillator as an operation power supply voltage.
Claim 8
Dependent Claim
116 words
The generator in accordance with claim 1, wherein said first and second selective activation means include first activation responsive to an output of said stable state detecting means and an output of said control signal generating means for activating said first substrate voltage applying means when said internal stepped-down voltage is unstable and a potential of said semiconductor substrate is shallower than a predetermined level, and second activation means responsive to the output of said stable state detecting means and the output of said substrate potential detecting means for activating said second substrate voltage applying means when said internal stepped-down voltage is stable and said potential of said semiconductor substrate is deeper than said predetermined level.
Claim 9
Dependent Claim
97 words
The generator in accordance with claim 1, wherein said first and second substrate voltage applying means include in common a ring oscillator including a plurality of cascade-connected inverters, and a charge pump circuit responsive to an output of said ring oscillator for generating a bias voltage by a charge pump function and applying the bias voltage to said semiconductor substrate, said first selective activation means includes means responsive to an output of said substrate potential detecting means for selectively supplying either said externally applied power supply voltage or said ring oscillator as an operation power supply voltage.
Claim 10
Dependent Claim
36 words
The generator in accordance with claim 1, further comprising means responsive to the potential of said semiconductor substrate for regulating a level of said internal stepped-down voltage for transmission to said second semiconductor voltage applying means.